I am with you on this - it's not impossible, but is it maintainable? what if I break a leg? and when something blocks and you don't know why, who can debug it? that's why we went for a different approach.

The problem with core.async is that it is an excellent PoC, but does not actually solve the underlying problem, that is "Hey! I want a new thread here! And I want it cheap.". Project Loom solves it. Of course, the problem is not something that could be solved within the land of bytecode.