What kind of ROI did they promise to their investors?

Ancient superyacht

Wasn't there some archeological evidence that many of the workers and their families were actually compensated?

Im not sure if its the great pyramid but I know some of the Egyptian great works were used as a jobs program during the off season of harvest.
Im sure the majority was slavery, but there was a tiny bit of good in those.

The profit motive was covered by the Pharaoh's exploitation of the entire nation of Egypt as his personal plantation and palace; each Pharaoh's Pyramid was the resulting useless passion project wasting all that accumulated profit. Albeit at reduced cost, considering the widespread use of corvee and legal limits on the ability of worker's to negotiate contracts with the agents of the Pharaoh compared to with non-government notables.

Slavery.

Archaeologists aren't so sure.
https://www.sciencefocus.com/science/were-the-egyptian-pyramids-built-by-slaves
- Who do you really trust on this topic: Lifelong scholars pursuing the truth with hard evidence, or the abrahamic texts?

I mean the artisans who worked on the pyramids were payed quite well. They even got buried nearby when they eventually passed away.

And no, slaves were not the ones building a the pyramids.

From what I have seen the newest consensus seems to be that they were essentially a massive jobs program.
- This is speculation but I'd bet there was some amount of less-than-voluntary aspect to the construction of at least some of the pyramids. As in "we'll pay you, but this is your job for the next 30 years while you're not harvesting."
- Should have just called it the pyramid scheme.
*paid

The ROI was eternal life

Do people just forget religion exists and believers take it fully seriously?

I honestly forget that frequently. My general attitude when any type of believer says something I consider obvious bullshit is to spend a couple of seconds thinking we're in on a pretend joke until it hits me.
In my experience the overwhelming maj{rity of believers don't. Theyll say they do and argue and gwt offended, bit its just an identity/social thing to them.
It's kinda sad,

Somebody once advanced the theory that the pyramids may have been public works projects, to keep the whole economy from collapsing. The pharaohs had accumulated so much of the available wealth, they spent some of it to put people to work. I think that's an interesting speculation.

So trickle down eventually works. You just have to let them get to godhood first. Got it.
Capitalism probably

Workers were paid. More interesting to ask why they built the pyramids.

'Paid'. When some egyptaboo tells you that "there weren't slaves in Egypt at this time", remember the 'workers' were paid in housing, bread, and beer. And were kinda bound by their duty to the God-Pharaoh. Totally not slavery!
Tho now thinking of it it's not like my wage stretches farther than that either...
Edit: spelling and punctuation are hard.
- remember the 'workers' were paid in housing, bread, and beer.
  That's more than many people will get today from a single job. 💀
🖐️Aliens🤚

tourtue: a more direct version of capitalism

they were actually paid labourers, the slave thing is a victorian invention i believe
- it might be more biblical but I'm no historian

Religion.

The ROI was outstanding if it facilitated their journey to a good afterlife well.

Death

It was a public works project, just like government jobs, infrastructure, and the military are for the US.

Motive was someone's huge fucking ego to be remembered forever.

Glory and worship is equally addictive as profit. The whole point was to have a badass setup in the afterlife. So you could consider this "profit"

It's how the labour caste paid their taxes

In medieval times that's certainly true. Egyptian laborers were paid. Generally in food and housing, as coinage wouldn't be introduced for quite some time. Especially skilled laborers were sometimes given land. Egypt had a very routinized farming season and most laborers were farmers with nothing to farm in the off season.
Skilled stone masons could kinda go wherever so locking them in to work with taxes was a great way to get them to leave.
Fun fact, they had a daily meal of a particularly thick beer that had chunks of bread in it. And one time they went on strike when they ran out of wigs.

I mean the pyramids were wholly improductive multi-decade undertakings, so that's not making the point you think it's making.

Probably brought in some tourism revenue

In other words, capitalism is in no way necessary for human civilization.

Of course it's not necessary. The democracy +capitalism combo is just the least worst setup we figured out so far.
- The democracy +capitalism combo is just the least worst setup we figured out so far.
  That's what the state propagandists tell us, anyway.
- The global south would disagree with you.
  Its working out pretty well for the wealthy in colonialist countries though.
- All of the democratic socialist countries would like a word. Unfortunately, the CIA already killed them all.
  Edit: To clarify, capitalism + democracy goes out of its way to fuck any other burgeoning system from getting its legs. So, I don't think it's fair to state "it's the least worst".

Aliens

It's real estate. They were playing the long game

Whips. Lots of whips and middle managers.

Were the Egyptian pyramids built by slaves?
The labourers would have been enticed by the mix of high-quality food and the opportunity to work on such a prestigious project. Today, many of the highly experienced archaeological workmen at the pyramids come from the same region, though they are paid in hard currency, rather than prime beef and accolades.
The Pharaohs were large plantation owners with enormous surplus foodstuffs, including livestock and garlic (which was highly prized for its medicinal value). And the workers were, in many ways, members of an enormous enthusiastic cult community that rewarded the construction of these mega-projects both economically and socially.
So, not all that far off from capitalism in the modern sense.
- I mean at the same time
  Ancient Egyptians were able to sell themselves and children into slavery in a form of bonded labor. Self-sale into servitude was not always a choice made by the individuals' free will, but rather a result of individuals who were unable to pay off their debts.[
  Several departments in the Ancient Egyptian government were able to draft workers from the general population to work for the state with a corvée labor system. The laborers were conscripted for projects such as military expeditions, mining and quarrying, and construction projects for the state. These slaves were paid a wage, depending on their skill level and social status for their work
  They used slaves for everything and paid them, so having a paid receipt is a weird distinction to try and make something less worse than it was.
- "Capitalism in the modern sense"
  You mean the wealth inequality, gig economy, being paid below a fair living wage, and unaffordable rent/bills keeping people in jobs they hate and aren't fit for?
  Sounds more like slavery now than what the ancient Egyptians had. Sign me up to build the next pyramid.

Slaves

I believe the most recent understanding is that the builders would have been paid, actually.
- We have the receipts and the village for the artisans. While it was difficult work they were well taken care of and well compensated.
- I wonder if, because that's how most of the world got things done for a little bit, we retroactively apply slavery as the only solution to how the ancients got stuff done?
The vast majority of people who built the pyramids were paid laborers.
Source
Nope, well paid workers who got vacation time and sick pay for such horrible conditions "stung by scorpion” (probably a metaphor for hangover), “bleeding wife” (wife on her period).
Oh.
- Not slaves, that is a myth.