Modern gnome is a pig, some of this could be tracked back to gnome-shell's use of javascript and css styling if you were so inclined. Most linux users don't really notice it due to the fact that most x86 machines are crazy fast.

OTOH, try starting a modern full blown distro on something like an rpi instead of raspian and you will quickly discover that you _NEED_ more than 4G of ram and a lot of CPU just to start firefox. Its even worse if you don't have hardware GL acceleration.

OTOH, the lightweight desktops (lxqt, lxdt, xfce) really are..