The people that bought Itanium-powered servers certainly weren't replacing them every 18-24 months. At the price they paid, you were looking at 5-8 years of computing before replacement. Or more.
My employer bought a pair of the final batch of Itanium servers. To replace 10-year old ones. This was an insurance purchase. The original plan was to shift all of that workload into the cloud, but that's neither going quickly enough nor is it saving any money. If you have a workload for which Itanium does well, it does it really well.
I was referring to the software vendors: why would they go through the effort of optimizing their code for this new architecture when they could simply wait a little while for the "old" one to get faster via Moore's Law?
cough IBM cough
They were never going to ditch power... Did they ever even have an Itanium product? I know they've had x86/x86_64, all sorts of power variants like Cell and god knows what.
I did briefly work on an Itanium system at IBM, but it was an HP box.
There's your problem.
Given the bajillion programs out there already, how many companies wanted to dig into assembly instead of just waiting 18-24 months for Moore's Law to speed up their software?
It's all very well and nice to have nice hardware in theory, but if you can't compile existing code to be fairly fast, then in practice you just have some expensive sand (silicon) in the shape of a square.
> People let their (understandable) hatred of Intel-the-company colour their technical judgement.
So getting back to your first statement: no they didn't. Everyone was basically all-in on Itanium. All the Unix vendors (except Sun) dropped their own architectures and steered their customers toward Intel. Microsoft released software for it.
But it seems the market didn't like what they saw, and just kept on with x86—and then amd64 came out and gave 64-bits to everyone in a mostly compatible way.