Sobering question and thread, Wayne.
I have spent a considerable amount and as was said above, (much of) the thrill is in the chase. Part of that is chasing a perfect shave, but also and increasingly new, "better" and fancier products. So function yes, but aesthetics increasingly. The limited capacity of brush and razor artisan brands like Varlet, Paladin and Wolfman feeds the never ending chase rather than the demand I'm afraid. And forums really don't help a floppy spined consumer like yours truly. Our grandfathers managed just fine with a single Gillette razor and a single soap...
All that said, shaving has become a welcome escape from reality, meditative me-time, something I feel I master in a world of, after all, more challenging and demanding things and pressure. Having a family calls for one's presence at home for the most part, as their families do for my real-life friends, so the low threshold for socialising virtually is also a factor. Plus, I enjoy my presence in here with you lot
These two paras in combination respond well to how and why my interest is kept up. One needs a hobby and at least for men this usually entails acquiring stuff (the sum of vices is constant, it is said, or to paraphrase, the sum of spending on "vices" is constant) but I could definitely put some more aside for a rainy day. I'm starting to reach saturation in gear, though, so it might be time.