For a long time i had a small Pentium III PC (released in 2000, though the hardware inside wasn't the best you could get at the time as it was meant to be compact instead of performant - it was in an almost pizzabox sized case) running Windows 98 for retro games and software (though mainly games). At some point i installed Visual Studio 6 to it too - and IME it launched instantly[0].

In general everything ran fast... except stuff that had to do a lot of disk access, obviously (i.e. installers and such). But i never though that the system didn't feel responsive.

Also many modern programs have splash screens too. E.g. have you tried to launch Gimp or Krita recently? Or Eclipse? "Heavy" applications never stopped having those.

Of course computers are much faster now, nobody is saying otherwise. What people are saying is that it often doesn't feel so. If my Pentium III can open Visual Studio 6 faster than my 3700X can open Calculator, then yes, things do feel more performant on the Pentium III running Windows 98 even if the modern machine is much faster.

[0] https://www.youtube.com/watch?v=h79Bt7h5ceo