Performance is overrated and irrevelant. It's simple force - not a skill. I can't do in more performat Firefox, neither it doesn't matter how performant Chromium, things that was possible in Firefox with old extensions. Not having such abilities, the only thing left to Google to talk about was.. performace - and crippling powers of Firefox. Rust is a new skill, not more of force.
Another skill, inconvinient, forbidden and forgotten ( * * * that I wish Ladybird will have * * * ): plugins - so I have A Browser For All Documents that can play every video format regardless of web video codec support or licencing etc. (with vlc, mplayer, whatever).
Neither Javascript shall be needed to see anything on the Web - if not being essential for tracking and ads
- but it's you who have to pay for it with that threadrippers (and no access to source data) ? Yes, it happend people are rich enough to belive that.
Making things simple and possible is the most important skill.
Check out this comment: https://news.ycombinator.com/item?id=40862781. While it's certainly possible to write the same parallel algorithm in C++, it wasn't done in Firefox before Rust, nor has it been done in Chrome.