Itanium was often misunderstood ...
... which soon led into misery, despite some quite promising points. And of course it did not help when the initial Itanium release had significant flaws, quickly leading to the deadly "Itanic" nickname.
The main problem was that Intel did commuincate poorly, so Itanium was widely misunderstood in the market. Many people dismissed it, simply because Itanium did not reach the same level of shipment numbers as x86 chips. Such people would also not understanding why trucks are more costly and somewhat slower than cars, yet do make very good sense in many cases.
Many programmers did not fully understand the implications of Itanium's EPIC architecture and the need to design and code differently than on x86. Not willing to adapt their behaviours, they got less-than-ideal results and did put the blame on the chip - not on their own ignorance.
In a wider context, we do not find not much big iron in IT any more. As per the above analogy, trucks have become very rare, and we do use way too many cars to get things moving. Not very efficient, and pretty expensive in total (although the single boxes are indeed cheap). Too many drivers needed, and IT budgets did not shrink.
Back to Itanium - yes, this relatively modern architecture is now dead, while we still use an 40+ year old architecture despite all its shortcomings. Is this a good idea ?
Just a small example - Itanium is not affected by Meltdown, Spectre and other speculative processing vulnerabilities.