I see some people saying it's not so bad. They are wrong.
Yes everyone can have different opinions about aesthetics, but structurally it's a terrible design.
Someone mentioned "but what if they've drilled receivers for the bottles" (like with forstner bits).
First of all it really doesn't look like they've drilled receivers for the bottles, and if they had the receivers reduce the thickness of the shelf right where it needs to bear shear load the most.
You can see that the top shelf is already warping from the hook tension.
What is the bending strength of .75" of salvaged wood? That's a really long span for that thin of a piece of wood to be loaded in bending. Shelf is going to be bouncy AF.
If you put a load in the center of one of the upper shelves, how much can it start to bow before the tension of the hooks is misaligned and pulls the load off the bottle column.
How will it resist parallel motion? Ie If someone pushes on it horizontally, parallel to the wall. Most layered shelves have metal hardware at the corners or a back secured at the corners.
On the middle shelves, are the upper and lower hooks severely misaligned, or are they very shallowly threaded, or are they threaded right next to each other? I don't think there's a good choice there.
Maybe I'm biased or cynical but imo the only person that should own or use this is the person that designed and built it. (Reap what you sow)
I built a shelf almost exactly like this in college except I drilled holes for the tops of the bottles to sit in. It held a big CRT and a bunch of other stuff for 2 years
The turnbuckles are tightened and it becomes really stable
I also built this a decade or so ago. It's still ok! Even loaded with probably too many books. The instructions I followed stipulated the holes for tops of bottles. And I used heavier bottles. And a double board thickness except for top and bottom levels. But we have no children. So the risk is just our own. Likely no worse than folks with glass coffee tables.