[mmmore]

Maybe it can but it sometimes doesn't.

I remember I looked into a lockup I was experiencing (this was a few years a ago so I forget the mode). Turns out emacs was writing to disk every so often and this was noticeably causing stutters in the main thread.

[aeonik]

You are correct, my emacs locks up constantly. Mostly due to linting and syntax highlighting, but also with the emacs terminal.

It really depends on the package, but too many fundamental packages are still operating in the main event loop.