In reply to Rick Gregory.

Yes, you can, but it's not so streamlined that it goes out to all WordPress websites, so that everyone benefits from the effort made by someone. Say, if WP core already integrated Service Workers to cache a website's assets, then a full 28% of the web would suddenly feel faster (there is at least a plugin for that, but it was not working fine when I tried it some time ago). But WP's competitors, whenever they implement a new technology, they can have it deployed for all of their customers all at once, making a huge and tangible step forward. In the medium to long term, I'd say that Shopify and all the other closed platforms will certainly be outperforming WP from a qualitative/performance point of view, making WP feel obsolete.