> it is hard to maintain two APIs.

This point doesn't get enough coverage. When I saw async coming into Python and C# (the two ecosystems I was watching most closely at the time) I found it depressing just how much work was going into it that could have been productively expended elsewhere if they'd have gone with blocking calls to green threads instead.

To add insult to injury, when implementing async it seems inevitable that what's created is a bizarro-world API that mostly-mirrors-but-often-not-quite the synchronous API. The differences usually don't matter, until they do.

So not only does the project pay the cost of maintaining two APIs, the users keep paying the cost of dealing with subtle differences between them that'll probably never go away.

> I do not prefer Python for reliable, high-performance HTTP servers

I don't use it much anymore, but Twisted Matrix was (is?) great at this. Felt like a superpower to, in the oughties, easily saturate a network interface with useful work in Python.

> I don't use it much anymore, but Twisted Matrix was (is?) great at this.

You must be an experienced developer to write maintenable code with Twisted, otherwise, when the codebase increase a little, it will quickly become a bunch of spaghetti code.