I'm not deep in on this stuff, but isn't Itanium essentially the only implementation is IA-64? Presumably Intel was pushing the envelope on their implementation of the ISA.
According to https://en.wikipedia.org/wiki/Itanium this is actually clear as mud and it seems Itanium was both a family of implementations as well as ISAs (thus variants of IA-64?). It's also the _only_ implementations of IA-64.
Going back to the original question (can RISC-V "become another Itanium"?), as long as there are people using/support/evolving it. Unlike Itanium, RISC-V has the support very many companies already and the membership list of RISC-V International just keeps growing.
The only thing that could threaten it would be a better alternative appeared or if x86 or Arm suddenly got the same unrestricted license. The former is not impossible, but it would be huge undertaking and by definition we would be in a better place. The latter seems essentially impossible.
As there's no technical reason why a RISC-V implementation couldn't have roughly comparably performance to an Arm core (iso-effort and technology) it's "simply" a matter of sufficient investment before we'll have the X1 etc equivalents. There are very many companies working on high performance implementations. One of the high profile ones is Rivos, but there are _many_ others.
