What does a more recent language offer that C# doesn't and that would enable more powerful IDEs?
Verified pre and post conditions would be nice. Especially in the era of LLM's, which can usually fill in the implementation given a sufficiently clear specification.
Eiffel is also well over 24 years old (but Albatross is more recent)
What's the problem? Golang is more than a decade old. Python predates Linux. Common Lisp with ANSI C is from early 90's too, but it began as Lisp in the 50's.