Everything is slower across every single facet of computing. Something is happening. I have a brand new Mac Studio M4 Max with 64gb of ram and every site is still slower than it was on a 2011 Mac Book Pro.
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.