> So far as killing HP PA-Risc, SGI MIPS, DEC Alpha, and seriously hurting the chance for adoption of Sparc, and POWER outside of their respective parents (did I miss any)?

I would argue that it was bound to happen one way or another eventually, and Itanium just happened to be a catalyst for the extinction of nearly all alternatives.

High to very high performance CPU manufacturing (NB: the emphasis is on the manufacturing) is a very expensive business, and back in the 1990's no-one was able (or willing) to invest in the manufacturing and commit to the continuous investment in keeping the CPU manufacturing facilities up to date. For HP, SGI, Digital Equipment, SUN, and IBM, a high performance RISC CPU was the single most significant enabler, yet not their core business. It was a truly odd situation where they all had a critical dependency on CPU's, yet none of them could manufacture them themselves and were all reliant on a third party[0].

Even Motorola that was in some very serious semicondutor business could not meet the market demands[1].

Look at how much it costs Apple to get what they want out of TSMC – it is tens of billions of dollars almost yearly, if not yearly. We can see very well today how expensive it is to manufacture a bleeding-edge, high-performing CPU – look no further than Samsung, GlobalFoundries, the beloved Intel, and many others. Remember the days when Texas Instruments used to make CPU's? Nope, they don't make them anymore.

[0] Yes, HP and IBM used to produced their own CPU's in-house for a while, but then that ceased as well.

[1] The actual reason why Motorola could not meet the market demand was, of course, an entirely different one – the company management did not consider the CPU's to be their core business as they primarily focused on other semiconductor products and on defence, which left the CPU production in an underinvested state. Motorola could have become a TSMC if they could see the future through a silicon dust shroud.

21 GB/s CSV Parsing Using SIMD on AMD 9950X