No idea how many 32bit apps I still use (on the iPAD 2 I cannot go to iOS10), but generally I am always surprised how much iOS (and Android) users critisize app pricing. In the classical PC world, programs (they weren't called "apps" in the old days
cost 20 bucks (for small developpers tools) up to several hundreds for consumer products (like Office, Photoshop etc.).
Spending 2, 3 or sometimes 5-10 bucks for an app is generally below my limit of thinking. As has been said here already, no developer can live by selling a 2-3 Euro/ dollar app ONCE to a client and then deliver updates for free for years. This approaches the "for free" concept. It may work for the few "super hit" apps that sell hundreds of thousands of copies, or even millions, but without being an insider: this is probably the absolut exception. For the rest the developers have to work and live. A few bucks (majority under 10$/€) every 2 years is ok for me, specially IF I use the app regulary.
BUT: it has to be communicated in an appropriate way. Silently re-selling the app with the wrong policy (life- long updates) is psychologically bad.