Depends on what you like. I enjoy buying stuff for each project so I would rather not build a huge stash. I would rather buy fabric for a pattern I want to do then look for a pattern that would fit all this fabric that I have bought. And I like new stuff. I have a bit of buyers remorse. So every time I go to the lqs I see something that I like better than what I bought the time before and wish that maybe I shouldn't have bought what I did last time. So it works for me to just buy what I need.
And not to offend anyone (promise) but I sometimes don't understand some of the stashes I have seen. Is there any real chance that they are ever going to use all that fabric? And when do you get to the point that you ever stop buying? I haven't heard anyone yet say they will NOT buy anymore fabric. There is always the exceptions of a bit more for this or something to match this. I also don't want to buy fabric that I wont use 5 years down the road. Am I still going to love it? Maybe, maybe not. Would I be able to find something that I love just as much later on down the road? Probably.
I think in the long run buying fabric on a need basis will be cheaper than buying a stash. Even with the rise in fabric costs. Good luck on whatever you decide