Sure its not a rival in some aspects yet, but the trend-line is pretty clear. Unlike ARM RISC-V gets to standardize the Serve Platform based on much of the work done for ARM but in RISC-V case when people will start to seriously develop these things the standard will be there already.
You already have RISC-V massively in the 'AI' market and some of these companies are targeting the data center, the famous example are Jim Kellers Tenstorrent and David Dizel Esperanto Technologies. In addition the the AI accelerators both these companies are also building high performance CPU.
In addition you have a lot going on in China as well, with large Chinese companies building on RISC-V instead.