Booting up is normally not done so often, but also doing other stuff takes way too long for my taste (over the perceivable 300ms threshold).

> Emacs ran on hardware from the 1980’s. How can it be too slow on modern hardware?

Since then they've added millions of lines of ELisp code. The comparison is moot.

Also we are talking here about Emacs "distributions" (Spacemacs, Doom Emacs) which come with a lot of code, and ELisp is not particularly fast.