While Linux helped, I'd argue the true factor is that x86 failed to die as projected.
The common attitude in the 80s and 90s was that legacy ISAs like 68k and x86 had no future. They had zero chance to keep up with the innovation of modern RISC designs. But not only did x86 keep up, it was actually outperforming many RISC ISAs.
The true factor is out-of-order execution. Some RISC contemporary designs were out-of-order too (Especially Alpha, and PowerPC to a lesser extent), but both AMD and Intel were forced to go all-in on the concept in a desperate attempt to keep the legacy x86 ISA going.
Turns out large out-of-order designs was the correct path (mostly OoO has side effect of being able to reorder memory accesses and execute them in parallel), and AMD/Intel had a bit of a head start, a pre-existing customer base and plenty of revenue for R&D.
IMO, Itanium failed not because it was a bad design, but because it was on the wrong path. Itanium was an attempt to achieve roughly the same end goal as OoO, but with a completely in-order design, relying on static scheduling. It had massive amounts of complexity that let it re-order memory reads. In an alternative universe where OoO (aka dynamic scheduling) failed, Itanium might actually be a good design.
Anyway, by the early 2000s, there just wasn't much advantage to a RISC workstation (or RISC servers). x86 could keep up, was continuing to get faster and often cheaper. And there were massive advantages to having the same ISA across your servers, workstations and desktops.