And it goes without saying that, for your own safety, none of these platforms will run code that hasn't been delivered by a trusted and approved corporate appstore.
The future of computing is very grim.
I think the main driving forces on this are:
1. It's easier for computer illiterate people to use web services, since they don't have to go through an installation process.
2. It's easier for developers to support their users because they don't have to worry about their users' computer environments, which is largely out of their control.
3. It's also harder/impossible for their users to pirate their software, since they it never runs in their machines.
I think the biggest reason (and the one harder to fix) is the piracy one.
I think your second point is actually the dominant one, but you're not wrong about this either. In some sense, we get the computing landscape that we (collectively) asked for.
I'm excited about things like WASM that will allow browser-based experiences to close the gap more and more with native apps. The web infrastructure is extremely powerful and has a fairly low barrier to entry so lots of people throw crappy experiences up, granted, but it's generally a good thing to have the resources so accessible.
WASM solves certain problems like arithmetic being slow. This doesn't fix the web's problems; it merely enables a new class of bad apps to be written on the web.
The best streaming video services are not web based. Thank goodness Netflix and Hulu have native iPad apps to spare me their websites.
As not everyone even has a network connection, I find this kind of viewpoint outright dangerous because it leaves out hundreds of millions of people. Streaming video, in particular, seems to choke if you don't if you don't have the absolutely best connection.
It doesn't matter that it's clunky and bad, CS people love working with hard to use systems, it just matters that it works.
google.com doesn't try to search my local drive. faceboook.com doesn't offer to share my local photos. Their usage of "browser as an OS" is extremely limited.
I worry about the other problem: the browser becomes so ubiquitous the OS disappears, along with any platform conventions and application interop.
I worry the next talented generation of developers is being alienated from the desktop, and as a result my computing experience will degrade as Chrome's piecemeal attempts to reinvent the OS leave me with an inferior selection of browser-based toys that are awkward and clunky compared to their native counterparts.
I grant the browser fixes a couple things my OS got wrong: installation/uninstallation and updates. But it feels like it does everything else worse.