Any purported explanation of Itanium's failure that doesn't even mention compilers once is at best incomplete.
> I won't be surprised at all if the whole multithreading idea turns out to be a
> flop, worse than the "Itanium" approach that was supposed to be so
> terrific - until it turned out that the wished-for compilers were basically
> impossible to write.
>
> - Donald Knuth 4/25/2008 in InformIT [0]
Years ago I read an interview of one of the upper managers of the project and his very brief post mortem was because Intel was focused on shipping only very high end chips, few to none of the usual people and processes that were responsible for the development of open source development tools had convenient access to the chips and so no motivation to do that work. That in turn forced Intel to do it and by the time the people making the decisions were convinced of that the willingness to spend money on the project had evaporated.
In a way he wasn't wrong - not many compilers and languages will auto-parallelize the code, you need to explicitly build it the way that enables it to run in parallel
The other part however is complete miss
>Let me put it this way: During the past 50 years, I’ve written well over a thousand programs, many of which have substantial size. I can’t think of even five of those programs that would have been enhanced noticeably by parallelism or multithreading. Surely, for example, multiple processors are no help to TeX.[1]
