>multiple millions of dollars

I can pretty much assure you the accumulated dollars invested over the years in making JS fast is likely to be closer to multiple billions combined.

You don't hear about it, but Perl has had many millions thrown at it too.

JS is probably closer to billions.

Not just orders of magnitude more money, but more importantly the large number of incredibly talented people working full time on JavaScript, in many different companies and research institutions, collaborating together. JavaScript benefits from an overwhelming network effect and critical mass of tools and developers, that Perl just can't touch, and never will.

Unfortunately it does not change bad parts.