Itanium is yet another example of how difficult it is to fight software ecosystem momentum.
It had potential but until you have an easy transition path, few will consider it. Apple figured that out during the 68K > PPC > X86 > ARM transitions.
Agreed, everyone has a pet architecture that fascinates them, but if its so good only 5 people can code for the target... it is e-waste within a year.
Apple is an exception as it has always had a walled-garden ecosystem with the OS, so can force shifts in architectures unlike most companies. The M3/M4 Pro series with unified GPUs is probably the best design on the consumer market right now, but people are not leveraging it as much as they would have in other ecosystems.
Have a wonderful day =3
Itanium 1 had hardware x86 compatibility and Itanium 2 had software x86 emulation just like Apple. It wasn't enough.