That's kinda revisionist. In fact ia64 owned the FP benchmark space for almost a decade, taking over from Alpha and only falling behind P6 derivatives once those started getting all the high end process slots (itself because Intel was demolishing other manufacturers in the high-margin datacenter market).
The point was that ia64 was certainly not an "inferior" ISA, It did just fine by any circuit-design measure you want. Like every other ISA, it failed in the market for reasons other than logic design.
No, that's pretty much exactly what happened. Were you there?
Beating everyone else at synthetic benchmarks is about as impressive as blowing away paper targets at the firing range. Real applications (and their operating systems) shoot back.
Itanium had some specific performance strong points. FP was one. Certain types of security code was another. In fact (and I may have the details somewhat wrong) but an HP CTO co-founded a security startup, Secure64?, on the back of Itanium security code performance.
But logic design is irrelevant beyond a certain point. Intel certainly had the process chops at the time and knew how to design microprocessors given a certain set of parameters. It's just the parameters were wrong (see Intel's late step-down from frequency on x86 above all else as well--driven I was told at a very high level by Microsoft's nervousness around multicore).
FP benchmarks are just about the most synthetic benchmarks there are though. They mostly matter to people doing HPC, and those kinds of workloads are often in the realm of supercomputers.
Which I think means everybody is saying basically the same thing, ia64 was overly specialized and had far too small of a market niche to survive.
The point was that ia64 was certainly not an "inferior" ISA, It did just fine by any circuit-design measure you want. Like every other ISA, it failed in the market for reasons other than logic design.