I think it's very much It Depends. With my fabric stash, I fairly recently realized:
(1) My sewing skills are not where they need to be to use some of the more difficult fabric. (Velvet and other pile fabrics, loose weaves, certain silks, many knits, etc.)
(2) It will be several months before I can really spend much time sewing, and after that it will be at least a year before I get my skills to the level I want.
(3) My taste in fabric changes a lot over time.
(4) Buying a new piece of fabric is part of what energizes my desire to sew. (Patterns are very different - having a stash of patterns does inspire me to sew.)
(5) I live in a very small house, I badly want that house to be neater, and books are a higher priority than fabric for me.
This meant that much of my older stash was not that attractive to me, and that I could pretty much expect that when I was ready to use the difficult pieces in my newer stash, I probably wouldn't like them much any more either. Once I added the fact that I really like to buy fabric as part of a sewing project, I realized that much of my fabric stash was pretty counterproductive. I've given away one _huge_ (slightly smaller than an appliance box) bin of fabric, and am working on giving away more. I'm keeping some unique pieces that still excite me, and a fair number of basics that I know I'll use - solid linens, solid wool crepe, that kind of thing.
It sounds like you're the opposite of me in many ways - you do sew on a regular schedule, you're skilled, you like already having fabric, your fabric feeds another hobby, and your fabric serves the whole family. So it sounds like it's worthwhile for you to devote a nontrivial amount of storage to fabric, and if you don't have the room, perhaps prioritize something else out of existence. That doesn't mean that it isn't worthwhile to thin it regularly, but I think that it makes sense for you to have a far, far bigger stash than, say, me.