> Firstly, I've seen a LOT of Windows 95 apps that do not "still run fine in Windows 10" -

Absolute most Windows 95 era 32bit applications run just _fine_ under Windows 10, period. Sans games. Games were often coded for then current GPUs and modern GPUs have different API.

> However, this is just factually false -- Windows and MacOS do not provide configuration GUIs for every possible setting.

I've not needed to use regedit in Windows or edit text config files since forever. You can fine tune stuff but absolute most people never need it.