I believe that putting everything online is not sustainable. It might be very difficult to believe for people who earn so much that they can afford 24/7 stable and fast internet anywhere they go, but there are places where even good old broadband dsl is unstable, in the west.
The reasoning of "appstore bad -> lets not use any appstores" is flawed. There are "appstores" like the ones on FOSS systems like linux (discover on Arch/Manjaro comes to mind), which show that you can make an appstore yourself.
All we need is to build a cross platform, community managed app store, which allows foss and non-foss apps, with a payment system. Thats the solution, not "make it a webapp".