So I'd bet on "he is delusional". When .NET gets a proper M:N parallel runtime it's when they will even enter the competition. They are not even in it right now.
Golang is miles ahead of .NET and it's far from many people's favorite tech.
But that's not how you progress.
Having proper M:N parallel runtime is mandatory these days and it baffles me that there people who are still not sold on it. I take it they have jobs and tasks where it isn't necessary but it's an interesting question to ask: for how long?
While mine was a bit tongue-in-cheek and apparently stung several people, it also has facts behind it. Working on many super-parallel tasks like, you know, good old web apps and APIs, have shown me that using regular threads does not scale.
There is tech out there that solves these problems and many C# and Java devs come off as grumpy curmudgeons instead of being proper techies and engaging arguments on their merit. And you seem to be another example.
Do better. The metrics and numbers are out there on the internet clearly showing that M:N parallel runtimes beat the classic threading model. That you might have chosen not to look for them is not a rebuttal by itself.
I do, which makes the rest of your comment a very boring ad-hominem.
I never said anything about how is the async runtime implemented. The problem is having certain runtime facilities, not the how below.