They barely exist in the network switch market. The new NVLink switches may change that for tier one inter-chassis transport to replace Infiniband RDMA, though.

Reality is Mellanox has never been a substantial networking player. Yes, in HPC, but that's a tiny market even today.

It doesn't help that Mellanox acquired Cumulus just prior to Nvidia acquiring Mellanox, and Cumulus was basically DOA. Now they are split SONiC/Cumulus with a lot of internal infighting trying to keep Cumulus relevant despite industry trends.