X86-64/AMD64 was solely developed by AMD and licensed to Intel.
I'm stating this because I can't tell what you mean by:
"wasted effort went into Itanium. But we ended up with x86-64"
I'm stating this because I can't tell what you mean by:
"wasted effort went into Itanium. But we ended up with x86-64"
What I last statement meant was we ended up by an industry dominated by 64-bit x86 anyway in spite of all the effort that went into an alternative 64-bit architecture. So we’d probably be in a similar place had Intel just decided Itanium was a bad idea from the start.
it’s safe to say that Intel has some sort of contingency plan going back quite a while. Some analysts even thought they saw features in Pentium that suggested 64-bit readiness.
But it wasn’t until Opteron’s success and its adoption by esp. HP and Dell that Intel felt they needed to make their 64 bit extensions plan public.
Random aside: Itanic was HP's brainchild that was adopted and refined at Intel (and far from all of Intel was excited about that). Having experienced a VLIW that _didn't_ suck (the internal engine of Transmeta's Astro 2/Efficieon) I'm sad that EPIC/Itanic gives VLIW as bad name. However, the future belongs to RISC-V.