Given how much revenue depends on the experience of a web app and loading times, I’d be happy to pay 100$ a month on that revenue if I don’t have to sacrifice a second of additional loading time no matter how clever I was optimizing it.

That 1 second of loading time probably has more to do with heavy frontends and third-party scripts, than the backend server's capacity.

$100 is peanuts to most businesses, of course. But even so, I'd rather spend it on fixing an actual bottleneck.

Not all businesses depend on milliseconds being shaved off the loading times

For example: Ticketmaster makes a ton of money and their site is complete dogshit.