alt Hacker NewsFX!32 was not good. DEC's own paper only provided results for "Byte Benchmark" (nbench) which is a few trivial compute kernels. Even that most favorable test they could find showed 500MHz 21164A performed about the same as a Pentium Pro 200, the core that would the next year be in consumer CPUs. It was also NT only, at the time not used for PCs. It's just not enough to be "as good" in a scenario like that where not only are you are massively disadvantaged by costs, but you have to break into existing markets.
EV7 and EV8 development did not go well either, costs and complexity was blowing out, EV7 slipped 18 months and planned 130nm shrink was not able to hit performance targets. EV8 was enormous and expensive totally unsuited to mass market commodity bottoms-up path of Intel, and exemplifies their retreat into high end niche rather than accept and embrace commoditization.
AMD licensed the EV6 bus, but of course there was no socket/pin compatibility between AMD and Alpha parts. So they still didn't have commodity motherboards, though that would only be one small part of the puzzle if they did have.
FX!32 was good compared to what was available elsewhere (including for Itanium IIRC). I am not saying it had to compete with fully with x86 on consumer desktops from beginning, but it would have been more stable position, especially with known upcoming work on 64bit-clean NT5.
EV7 I am interested in more details because I want to know if the slippage was part of the original development run, or the post-Itanium one when it was restarted by HP. EV8 was admittedly dead in the water but I would say not so much for technical reasons as much as for direction options available (vs. following the samsung partnership to bring more AlphaPC-like systems)
The motherboard difference was slight between K7 and EV6 parts from my understanding if there was a will to commit to large scale production (arguably EV67 could be probably made into pin-compatible packaging even). But admittedly small part.