Go has pretty good introspection with pprof it's enough, you don't need something heavy like JFR. For debugging delv is ok, not on part with C++/ Java but it's fine, you can even do remote debugging now.
The thing is with Java and to some extend C#, yes they have different runtimes, VM, AOT / JIT etc .. different thing to compile to native binary: none of them are really mature atm and moreover it's even more complexity for the programmer, now he has to choose which runtime or compiler he's going to use, it's crazyness. Same story with the GC Java offers, too much choice, too much burden on the programmer. For app A you're going to use this GC + runtime, app B is going to be different, it really mess up the dev / ops process.