I think if you want to play this game long-term, you should probably up the ante a bit
I've had such wake-up calls several times every year, beginning with my first year earning a living via the web. And it just keeps happening.
When Google first began talking about The Need For Speed [webmasterworld.com] in 2009, and Steve Souders published two books about his research, that was just such a moment. And I went down the rabbit hole - learning about all kinds of things I had been ignoring, such as eTags and how browsers multi-thread their http calls.
Still, the basics I learned in the 1990s are still the core of faster pages for me. Image compression is one very big deal, as well as understanding how browsers cache various objects. This information is well worth putting into practice, and it leads to much better comprehension of how these interwebs work.