It's also possible to say that the 6502 and 6510 were perhaps the very last processors that I understood in real, intricate detail. Once I hit the 286 it might as well have run on magic pixie dust. I can't remember ever masking interrupts on an x86. I've only written in languages at the level of C or higher ever since., and I've never embedded assembler to fine-tune performance.
My experience, also. While I did experiment with interrupts with x86, I never did much with assembler, on them, and the segments, near and far stuff, definitely discouraged one from getting too deep into it.
So you think that money is the root of all evil. Have you ever asked what is the root of money? -- Ayn Rand