This is a strange position considering I would rank the JavaScript engine as, bar none, the most complex and difficult part of the entire browser stack to develop and keep maintained, and it continues to grow and become more and more complex along with the runtimes implementing it, which were already incredibly complex by design.
I don't disagree--though I know people, including myself, who have managed to pull off either all of or most of the work required alone--and so in an argument about the JavaScript engine I would argue it should be a VM only, such as WebAssembly.
(As for accessibility, I appreciate you might find my wording funny, but it isn't a laughing matter really.)
> behaviors people liked, such as accessibility
lol