> Itanium motherboards never became a thing from the top-10 sized Taiwanese motherboard makers

Supermicro and pretty sure Tyan offered Itanium motherboards.

From what I remember the Itanium was always harped on as too complex and too power hungry for mainstream while offering abysmal x86 emulation which soured its adoption. It had a niche in certain industries like HPC and high reliability. AMD's x64 architecture launched only 2 years after Itanium launched and pretty much destroyed any future for Itanium.