It never really was. Google just follows the user. If a site offers the most relevant content for a search query, then it’s what the user wants to see, whether it takes 500 milliseconds longer to load or not. Only if different sites have exactly the same ranking otherwise, then maybe your ranking position changes a bit. But in general, search results are not ordered by speed. That would be ridiculous.
Optimizations are still useful of course, but there is no reason to obsess about them. There are much more impactful changes to be made on the site itself, e.g. how to name pages/forums/topics, how to structure a menu and so on.