That ship has long since sailed. The web is the preferred framework for creating "non-native" (maybe nomadic? colonizer? invasive?) apps that largely ignore their host platform in favor of being the same everywhere. For better and worse this is what developers and designers have always wanted out of portability.
It's also what I, as a user, want. I don't want some middle-man corporate "platform" (of which there are very few to actually select from to suit your personal tastes) inserting their vision of what UIs should look like into interactions between me and the service I'm connecting to. I want my platform to be as invisible as possible and interchangeable with other platforms. The more things stay the same when switching between platforms, the better.
It's also a lot easier to learn the 2-4 dominant UX paradigms of the dominant platforms than the hundreds we have now with everyone doing their own thing. Doing remote tech support for elderly relatives is hell when you can't even rely on a menu bar being present/useful.
This is a rather bad way of making portability. It is bad for accessibility (even though they tried to add things to improve accessibility, it does not work very well), for working on multiple types of computers (since, then the software specific to that computer cannot do so by itself, and instead needs to use the specification of the received file, which is probably wrong anyways), and for many types of features that may be helpful but that are unavailable or are not designed or implemented well. Furthermore, WWW is also, not work well with multiple programs and with user customization very well, pipes, etc. And, it is complicated to implement and does not run efficiently. And, there are many security issues, having to be made more complicated just to avoid some of them, in ways that would not be necessary if it were designed properly. And, anyways, it cannot be the same everywhere, even if they want it to be.
This is mostly a question of costs & availability of developers. There's simply not enough native developers on the market, and the good ones can ask very high salaries.
Hiring N teams of M developers for N native apps, compared to hiring K<<M web developers is way more expensive, difficult, and slow.
Or seriously, working on software ecosystem preservation just to preserve it it is absurd. Things get replaced because people want, and at this point you are just trying to force people to use things they against their wishes.
