It's a fact that Intel's lastest Pentium 4 CPU has MMX, SSE and SSE2 extensions while AMD's Athlon XP has MMX, MMX+, SSE, 3DNow! and 3DNow!+. Why is Intel not including AMD's instructions inside their CPUs? Pride? AMD had taken Intel's MMX and SSE technology! (And the SSE2 too in the Clawhammer) What does it symbolize? Is it a good decision to exclude AMD instructions inside Intel CPUs?

Probably a few reasons;
A. They'd have to license it (Well, I assume so anyway).
B. Them supporting it would be like them saying AMD has a better Instruction set.

Does it mean that AMD is trying to say that "Intel has a better set of Instructions than us?"