FWIW, C# generics are way better (ergonomics) than the Java ones (due to type erasure), so Java waited too much. History is more complicated though for Java, since it was either having some generics vs having none. See [this](https://softwareengineering.stackexchange.com/questions/1766...) for a lengthier discussion.
C# was meant to have generics in day one, but it didn’t make the cut and it was introduced on the next version (2.0)
Yes, .NET had the benefit of coming second and using F#, which was originally essentially OCaml 4 on .NET, as it's testing grounds. Same for Async
I am considering .NET for one of my compilers backends because of the reified generics. .NET can even pass around an object with generic methods that get specialized via JIT at runtime each time it sees a new data type (with reference types sharing implementations). Which also ties back to having true value types
It's a shame it took so long for .NET core to come around because even today the platform carries a reputation for being windows first which hasn't really been true for many years now