For me, the GIL is a feature. Proper pthreading is for systems software as I see it. If you're rewriting Apache or IIS then you may need to bring in Rust, C(++).

I never found platforms like .Net and Java to be low level enough to write systems software, where you'd definitely want multithreading, and not high level enough to be as convenient as Python.

I write in Python and then use PyPy for more CPU intensive services. If I wanted multithreading and instances won't cut it, it would be a pretty hardcore usecase (for a lone wolf like me), I'd most likely also need no GC so I'd reach for something like Rust rather than C#.

I hate to say "no" to learning anything, but to be the devil's advocate this is how I've always seen it.

In the public repos, there no substantial new work taking place with IronPython.

If there was enough interest you could get the Microsoft Python team to support IronPython. There's been talk of a renewed effort.

[1] https://blogs.msdn.microsoft.com/pythonengineering/

The performance of IronPython was horrible and Python being an ecosystem of libraries built in C and wrapped in a Python API, it makes alternatives to be unusable, since most Python libraries that matter are incompatible.