No, even a big cheese can't press itself, unless you want a really open texture like a Blue. There has to be sufficient pressure applied equally to the top surface to squeeze out excess whey and meld the curds. Wayne is doing bigger cheeses and using lots more weight. Farmer is using
750 to 1500 pounds on his big press to achieve 10+ PSI. ... and still wanting a better texture.
PSI is a known constant regardless of the cheese size. Weight however is completely variable depending on the hoop size. Sort of like waiting a certain number of minutes until you get a clean break. Yes, that works, but milk chemistry, rennet quality, and temperature can be different every time you make cheese. So the flocculation technique compensates for these variables and is way more accurate with predictable, repeatable results.
Obviously, a large rock CAN work "just as well" as a pneumatic commercial press - as long as you you use the same rock every time and don't change hoop sizes.
Almost anyone can make cheese. It's much harder to make really good cheese with consistent results. When you buy a good beer, you know pretty much exactly what a given brand is going to taste like. If a beer was markedly different every time you opened one, you probably wouldn't buy it. Artisan cheeses are the same way. If they are different every time, they are not marketable.