Without AMD rescuing x86, PowerPC wouldn't have died. MIPS wouldn't have died, and faces with the need to brake the 4Gn barrier on consumer equipment microsoft would have had windows running on three or four competing architectures until 2013 when everything would have switched to ARM.
Itanium would have already been a rotting corpse.
AMD rescued Intel from its own management.
WindowsNT is remarkably well suited to porting to other arch. This was done on purpose to hedge against x86. Dead one day, reactivated the other. MS needed to brake the 4Gb barrier and they would have done anything to get consumer priced 64bit chips.
Itanium was a dog. We had an Itanium SGI "supercomputer". Everything about it that SGI designed was amazing (hot swapping cpus). The cpu was a dog.