> It's frustrating that "filling a niche and filling it well" is just anathema these days
On the contrary, a lot of (offline) companies are deciding that diversification is bad and they should divest everything outside of one core business. Be it ThyssenKrupp, Alsthom, Bombardier, GE, Phillips, take your pick.
However many web companies choose to diversify. Why not? It helps them retain and gain users, and protects them against heavy hitting competitors (FAANG can copy your business model and features quite quick). E.g. take someone like Snapchat - their features were copied by competitors and they had no differentiator, so they floundered. A Telegram or Signal was little differentiation bar potential diversification, which is why both tried some crypto crap.