Also in my experience, relying on small-scale FOSS apps means opening myself to the vagaries of their on/off development cycles, dealing with their underinvestment in design, and the impossibility of them spending significant resources on good old fashioned centralized backends. Of course FOSS apps have many strengths of their own (esp. in the desktop content/code creation category), but the apps on my phone are "lifestyle" - I want them to be rock solid, aesthetically pleasing, to require zero thought, and to respect my privacy, and I'll happily pay good money for that, which is something I think in this day and age should be encouraged. FOSS apps are simply a different value proposition.