Yes. Companies with existing workforces are doing new software all the time. If you have a workforce with let us say 100 devs. Even if you hire 10 new ones temporarily or permanent, you for sure tell them: use what the other 100 do. It is not maintenance what drives this, it is the lack of momentum in your work force.

And that is very okay. (Modern) Java and .NET are excellent choices. There is nothing wrong with them.

It is a good choice if you want to use a non-Microsoft stack language (yes C# can be developed on Linux but the quality of the development experience on Linux isn't same as Windows) and want a vast ecosystem. Golang is too verbose due to lack of exceptions and the size of its ecosystem of third-party packages isn't anywhere as close to Java's. Swift is very nice but issues with ecosystem exist there too. Too steep a learning curve with Rust so more difficult to find developers. Modern Java has improved a lot compared to, say, Java 8 with record types, pattern matching, multiline strings etc. The pace of new features coming to Java has been quite high in recent times. Plus there is always the network effect.

Java is still the default choice for many for enterprise software. Job-focused courses and curricula all over the world are still leaning big on Java ensuring a steady and large pool of okay Java devs.

Job focused Bachelor courses and curricula highly outnumber rigorous CS courses like the ones you are likely to find in MIT, UCLA-B, IISc, IITs, Oxford, UCL, Tsinghua, Peking, etc.

Yes, outside HN praises of Elixir, Gleam, and co, corporations run on boring technology, maybe with exception of what the FE folks pick up on each project.

They work, have great tooling, and do whatever is required for customers.

Yes. Many startups using Java in europe