C# and .NET are most heavily invested in by Microsoft which owns and steers its development, that is true. It is also true that JVM world sees investment from multiple MSFT-sized corporations.
And yet, despite the above, it keeps moving forward and outperforming Java on user experience, performance and features despite being worked on by much smaller teams. I think it stands on its own as a measure of a well-made technology.
In addition, you can look at source code and contribute yourself, 90% of what makes .NET run is below. Almost all development happens in the open:
https://github.com/dotnet/runtime
https://github.com/dotnet/installer
https://github.com/dotnet/roslyn
https://github.com/dotnet/aspnetcore
Could Microsoft do a better job at making it even more community-facing and attempting to make the .NET foundation as a sole owner and steering committee of the language itself? Sure. But it's not that bad either today. Quick reminder - Oracle is not exactly a saint, perhaps even worse (MSFT has never gotten into any litigation even remotely related to .NET or C#).As for career opportunities, as other commenters would note, this is highly specific to a region and does not translate globally. Again, we are discussing the "how good the language/platform is" first and foremost. I don't see startups adopting Go because of the market or trusting Google not to rug pull them...so perhaps we can do a better job so the next language of choice they pick is C#, which has much higher ROI in the hands of the good developers (for example, it can be very easy to adopt as a second language if you are well versed in Rust).
It has features like LINQ. It has routinely had a lot of good updates, new features always coming out, increases in performance, etc. The primary thing lacking has been good support for developing and deploying on Linux, and a couple other devops-related things. It's a shame to see that holding it back, but at least MSFT actually opened up Linux support at all (nobody thought they would).
I'm not sure what vested interest MSFT had in some of the changes introduced for iOS in .NET 8, but now it can be targeted with NativeAOT too, so there is clear investment and dev effort both from community contributors and MSFT employees to support various platforms.
Somewhat arbitrary example, there is also a project to support RISC-V (https://github.com/dotnet/runtime/issues/84834).
Azure is also the big moneymaker, so these days they want all their technologies to have Linux support since that's the dominant cloud OS.