Itanium was the wrong design not because of the reasons you suggest, but because it assumed that good performance is something that can be statically baked into

Itanium was the wrong design not because of the reasons you suggest, but because it assumed that good performance is something that can be statically baked into the object code, and therefore that there is such a thing as a sufficiently smart compiler for an explicitly parallel processor running general purpose code. But evidently the designers were wrong. Which is not to say that explicit parallelism is bad, it’s clearly useful for GPUs and vector code (and compiling to SVE is not too different from itanic). But it doesn’t work as well as dynamically discovered parallelism for non-vector code.