My experience of J2ME phones (as someone living in India pre-iPhone) was that the Java functionality went unused, except as far as it was used to implement vendor-written apps.
ChromeOS benefits from the fact that it is just a web browser - if you want just a web browser rather than a generic operating system, Fuschia is of course unnecessary.
Nobody targets webOS, and I suspect people’s choice of TV has more to do with how it looks on the in-store display or how cheap it is than what apps you can run on it.
FreeRTOS, mbed and IncludeOS are not generic operating systems in the first place.
There are essentially no “pure” ISO C or ISO C++ programs - everybody uses system-specific libraries at some level.
Basically, Fuschia suffers from the fact that a large amount of userland will need to be rewritten for it, depending on what market segment it targets. (“Just” being an alternate Android runtime for phones, as an example, wouldn’t require this.) This is an obstacle - not an insurmountable one, but being non-POSIX is an obstacle for any OS, that the people behind it need a strategy to tackle. Whether or not people will code apps for Fuschia will depend on how excited developers get about it at first, and then how many people use it.
Of course it is. It’s not a good thing - it’s essentially killed any possibility of a capability-oriented desktop OS for a number of years, for a start. But it’s the state of things - if someone can’t run at least most of their software on a new system, it’s a massive barrier to adoption.
The reason Android and iOS got away with it was that nobody was really running important software on their phones in the first place, so it was a brand new capability that didn’t need to be compatible with anything.
Mostly because being POSIX compliant makes it far easier to port a lot of command-line and server-side software quickly. Most new operating system projects don’t have the manpower to rewrite the world - I think the last major one was probably Android.
> Why don't we have have sandbox execution environments in the OS itself?
Well, if you try, you wind up with something that looks an awful lot like a web browser - especially once WebAssembly is a thing. The API that many desktop operating systems provide is not designed for the security model that you're looking for, so you wind up building a new one on top of it - see WinRT when Microsoft needed a sandbox.
We used to have things like Java Web Start (still do in some enterprise systems), and, well, it's not exactly any better than a web browser except that it has a better view layer for applications than HTML/CSS. It's also not supported on mobile platforms.
Really, only on HN and other "startup forums". Anywhere else... well, do you think even an ice cream stand is immediately a viable, profitable business? Usually not. The space between "having a registered company" and "actually in the black and stable" is a startup.
And if they're not using 4 spaces, they're not following one of the more important documents there is for coding in Python in a way that other people can easily read - PEP8.