This might just be a type of confirmation bias. The only PHDs from "then" that you know about are the ones worth recording in history books or have long-lasting impacts. Everyone else just gets forgotten
I actually had an offer from my advisor to study for a PhD under him by basically taking on a major coding project to develop a non toxic format of social media, or at least to get as close to that as possible. I also remember it involving some non crypto uses of blockchain software potentially but my prof was more interested in the complex web development aspects of it and actually got my web design professor in on pitching the potential for it to me.
We had me enroll in a master's level web design class to trial run it, and it turned out I wasn't the webcode wunderkind they thought I might be given my good web design work for my courses so far. I'm creative but not a savant basically. We all agreed that my PhD potential was best sought after more design experience got under my belt.
I thought the whole deal with PhDs was that they were supposed to be new research that pushes the field forward. What field were you studying? What was the academic contribution the prof was expecting?
Software Engineering, and it was more intended as a build project than as an academic venture. We would basically have been setting out to strip out all the addiction features Social Media is built with and see what can be built with what's left and what new ideas can make it a good experience for the user without queuing them for ranked rage fest matches against whoever else is in the comment section they clicked on in the rage bait article.