At the end of the day if a language proves popular enough in other domains outside of the area which is directly controlled by the language maintainers, then the community will usually find a way of taking over maintenance of it.
We've seen this with Pascal, various BASIC dialects (including Visual Basic), and to an extent Java too. The problem with Objective-C was that - as far as I'm aware at least - it wasn't widely used outside of Apple / NeXT's ecosystem so if Apple deprecate support for Objective-C on their own platforms then there's little incentive for the community to keep using language (much like the problems with Visual Basic - which is why few know about it's open source forks). But languages like C# and Go are used massively across a multitude of domains so even if MS/Google were to kill them tomorrow, the community would almost certainly find a way to keep language alive. Heck, Go might even become more popular if that happened since many of the complaints against it are down to the highly opinionated approach of the current leadership.
Let's also not forget that Go and C# tooling are open source so the community wouldn't have to reinvent the wheel like they did with Delphi / Object Pascal and Visual Basic.
Whoever is smart will take note of what happened to VisualBasic and is happening to Objective-C.
If one evaluates C# they should obviously look at what MS are doing. Same thing for Swift and Apple.
In short, we're quite safe in terms of if C#, Swift and Go will live on. They will.
C# and to some extent Swift are also two huge platforms, there are very few organisations out there that would be able to steer their development.
Finally, they are not standardised in any way. MS tried something with 2.0 and then gave up.
My impression is that these two live and die by the will of their corporate masters. I'm not saying they will kill them or anything, that would be pretty stupid of them to do.
They are standardized, you just need to look at the right place.
https://docs.microsoft.com/en-us/dotnet/csharp/language-refe...
https://docs.microsoft.com/en-us/dotnet/visual-basic/referen...
C++ is one of the healthiest languages in existance. It hits all the important checkboxes of standardisation, wide industry and platform support and large community.
It is just like trying to compile the Linux kernel with clang instead of gcc, with the source code full of gcc extensions.
Please note that I am not demeaning your statement. It's a legitimate curiosity on my side.