Itanium was also, in many ways, designed for a world where ILP, rather than TLP, ruled. That distinction wouldn't become terribly important for a few more years but it would have eventually. Intel made a number of decisions in this vein. See also NetBurst Architecture. (An Intel exec told me, at some point after it had become obvious that multi-core was the future, that Microsoft had really pressured Intel to go down the few/fast cores route.)
If we switch from the "Every year the clock rate goes up 30%" model to "50% more cores every year", you're going to trigger the "recompile the universe" event. This is an esistential-level threat for the Microsoft of 15 years ago.
Microsoft's biggest selling point for years was the backwards compatibility. Keep running that old software forever, and the magic of Intel running the clock up means it still gets faster every year.
If that train stops, you may well think "if I have to rebuild anyway to support many-cores, why not do so on Linux?"
I could argue it was doomed from the beginning as well for various technical reasons given how the industry evolved. But there's at least an argument that better time to market might have been enough to get established as a dominant 64-bit architecture.