This is very shallow short term view on things. Performance also impacts customer retention, loyalty, satisfaction and word of mouth advertising because of that, makes engineers feel good and proud about the things they do, rewarded and motivated to keep going and not leaving to do something else, etc. Hardly "a waste of resources".
Assuming "fast enough for a good user experience", expecially early on in a product lifecycle, I prefer to focus on development speed than product speed.
I get your point. This is an outlier, but hear me out:
For some of the workloads I run on https://workers.dev, I can tell you that going from 100ms to 10ms is something I look for every single day. I am also very interested in anything that takes the memory usage down into KBs from high MBs, say.
In 2020, a webpage that "only" takes 10 seconds to load is a miracle of performance and user-friendliness. Load times of up to a minute are the new normal.
I'm pretty sure dismissive comments such as yours lead us to this bad place.
Of course by "load" I don't mean TTFB, I mean actually loading the full page, including all the spinners, reflows, banners and toolbars popping into your page, images, etc.
