So what you're really saying is that green threads are a good thing.
One of the biggest strengths of Erlang (and Elixir by extension) is that they take the approach of finding practical solutions to real problems.
Sure, theoretically there might be a better solution than green threads, but like you said, we're still waiting for that better solution 30 years later. In the meantime, Erlang has been powering highly reliable and concurrent systems for ~30 years now.