Web developers should be forced to use hardware that's roughly at the 10th percentile in performance of their user base, not the 90th. Alternatively, make performance a WCAG concern.
I don't think this would help, if a site or SPA performs terribly on a high end machine, the only conclusion I can draw is performance testing isn't tested or validated at all.
Chrome Dev tools, and hopefully others, have a performance monitor option that lets you throttle the CPU and throttle the network. It should be plenty possible to test performance of sites on simulated 10th percentile systems, but this just seems low priority.
