An underrated factor in this conversation is implementation effort. Javascript is arguably the most widely run interpreted language in the world. Pre-Chrome, JS was uniformly rather slow, but Google was betting on webapps being good and usable, so they brought on some top-tier compilation/VM talent to build V8. As fast Javascript existed, it made it possible to do more natively in the browser, and other browser vendors joined in an arms race there. Tons of effort overall, tons of money and time from top-tier experts.

There was no equivalent competition between major organizations to make Python fast. Folks have tried, but not on the same scale. Yes, factors like language design and existing ecosystems entanglements played a role here, but if Python had the investment in performance Javascript had (financial and expert attention), it'd be dramatically faster today (though it may have required a fork or similar, depending on how tied to simplicity Guido was feeling).

To be clear, I'm not saying nobody tried to make Python faster, or that Python devs don't know what they're doing. I know very well both of those things aren't true. But, the kind of sophistication required to make Python fast in absolute terms is very hard to build and maintain, and for various reasons nobody who has found Python to be too slow has found "invest in a bunch of person-years of VM engineer attention dedicated to performance work" to be their best path.