MacOS is similar but better. The sandboxing and permissions were planned and implemented long ago, and getting a new app is as simple as downloading its .app bundle and running it.

MacOS apps are sandboxed and signed by default now. The biggest problem I see with sandboxed apps is they require more disk space and ram, for example each electron app can’t leverage the same underlying WebKit engine. The real benefit is that you don’t have to worry about incompatible dependency versions wreaking havoc on your system. It’s very difficult to modify the underlying OS, which is overall a good thing for most users.

Mac OS X is based on some really good design, portability, security, and development environment. BUT some of the direction Apple has been taking for the last decade+ has made the platform less open and a lot less appealing to me (and others in my family).

I give them credit for vision that matches what some people want, and providing and experience that just works within that vision, but that vision doesn't match what I want (or even need) from of desktop anymore.

The very fact that they work like mobile apps is a reason to dislike them, honestly. At least Flatpaks aren't total fucking crap like Snaps.