> because who would want to buy a Pentium Pro when the better-in-almost-every-way Pentium MMX

Maybe this was satirizing people running after every shiny new thing, but the MMX certainly wasn’t. The Pro was the first P6, a totally new, out-of-order microarchitecture that the Pentium 2 would be based on. The MMX was a standard P5 Pentium with a larger L1 and the MMX vector instruction set which, while the first of its kind in an x86, was ultimately not used much in applications, partly because it was integer-only (also because it awkwardly co-opted the existing FPU registers rather than having its own register file). In any case, the Pros were expensive and meant for business use, while the MMXs were consumer processors.

Just one caveat: the Pro overlapped in time with people running a lot of 16-bit code, and I think the Pentium MMX was faster for that, or at least that the Pro didn't offer much edge.