Nit: Thunderbird was the third iteration of Athlon and I only remember this because I had an Athlon 700, which came on a Slot A cartridge (!) and had the L2 cache as separate chips
That same system also had one of the first GeForce cards. The term "GPU" was not unknown before GeForce, but it was the first time the mainstream computing media started using it regularly.
That was the first computer I built with my own cash and boy it was not cheap. (21" CRT monitor and dual 10k RPM SCSI drives...)
10 onward just seems to lag & crash more. Totally crazy theory would be that binary compatibility (and dependencies) doesn't work well once the original author of a piece of code has retired (or died).
For dev and desktop usage no IGP has let me down. Unless work needs a dedicated GPU to be done I think an IGP is enough for everything else these days.
I don't think people using dedicated GPU wouldn't see differences with an IGP in day to day usage.
Nowadays, I have no idea if that advice (Intel + Nvidia) is still sound. There are way more AMD users than before, and computers are more complicated than they were 20 years ago.