@DeadwebsiteBoringcommunity, in theory, "ppfd=yield" until you take into account other factors. One factor is the growing room. If you put my light into a black nylon tent without the reflective walls, so that you had zero reflectivity, you're not going to get the same yield I'll get in a grow tent with mylar even though the PPFD is the same. And I've read that the mylar in a modern tent is so good that it multiplies your PPFD by 25-33% depending on type and how much its reflecting (how close it is to the light).
Other factors are humidity and heat. Both can impact yield all by themselves. So can grow techniques and nutrients. So you're being reductionist to the point that you're wrong - there are too many other variables that have nothing to do with pppf but will impact yield.
There's truth to what you say to a point, but not to the degree you make it so I disagree. That's the problem with reductionist reasoning: it is too simplistic and it does't take into account variables that matter.
like