Sure, the details would certainly have been different, but my argument is that the end result would not have been that different from what we saw playing out.
My quick 5 cents for what might have happened in the interim:
- Without a separate high-end offering in the form of the Itanium, Intel is quicker to adopt x86-64, and produce high-end server chips with extra RAS etc. features.
- POWER and SPARC, being the last holdouts in the RISC market in our actual timeline and outliving Itanium, would likely not have been affected much wrt. Itanium existing or not.
- SGI with MIPS would likely have been the first one to fold. Would SGI have pivoted to x86-64 & Linux sooner than they historically did, or would the company have gone bankrupt first?
- HP/Compaq with PA-RISC and Alpha is perhaps the most interesting question. HP did a lot of early VLIW/EPIC research with an eye towards developing a successor to PA-RISC. Would they have thrown that R&D away and selected to focus on either PA-RISC or Alpha after failing to secure Intel as a partner in the Itanium? Or would they have tried to develop something Itanium-like without Intel?
Another interesting what-if, if Itanium didn't exist, would instead 3rd-party manufacturing of high end chips (similar to TSMC today) have been developed sooner than historical? Keeping in mind that a large reason for the Itanium was accessing the semi process R&D and chip manufacturing prowess of Intel, as the thinking at the time was that tight (vertical!) integration of the chip design and manufacturing was a requirement for the highest end CPU's. And it was the spiraling costs and volume required of chip manufacturing that was the boat anchor around the necks of the RISC vendors moreso than the chip design itself.
