I doubt that Itanium would have ever perked down to consumer level devices. It was ill suited for that workload because it was designed for highly parallel work loads. It was still struggling with server workloads at the time it was discontinued.
At Itanium's launch, an x86 Windows Server could use Physical Address Extension to support 128GBs of RAM. In an alt timeline where x86-64 never happened, we'd have likely seen PAE perk down to consumer level operating systems to support greater than 4GB of RAM. It was supported on all popular consumer x86 CPUs from Intel and AMD at the time.
The primary reasons we have the technologies we have today was wide availability and wide support. Itanium never achieved either. In a timeline without x86-64 there might have been room for IBM Power to compete with Xeon/Opteron/Itanium. The console wars would have still developed the underlying technologies used by Nvidia for it's ML products, and Intel would likely be devoting resource into making Itanium an ML powerhouse.
We'd be stuck with x86, ARM or Power as a desktop option.
Had it not happened, PC makers wouldn't have had any other alternative other than buy PCs with Windows / Itanium, no matter what.