No, that's not it at all. Itanium had huge problems straight out of the gate - it ran hot, slow and very expensively. I think ultimately it boils down to compil

No, that's not it at all. Itanium had huge problems straight out of the gate - it ran hot, slow and very expensively. I think ultimately it boils down to compile time optimisations not being enough and Intel having to throw everything at it to make the shortfall.