Infiniband is a monopoly from NVidia (Mellanox). Everyone else would much rather use Ethernet which is the actual industry standard.
Infiniband is not fun - it's a special snowflake of an interconnect that sits parallel to the rest of your datacenter network, and can not really run a standard TCP/IP codebase (yeah IPoIB is a thing but still). Do the Nvidia boxes really need a scale-out IP network as well as an Infiniband network?
Plus the spec is old. Packet spraying and trimming, better ordering guarantees, queue pair scalability... a whole bunch of enhancements have been incorporated into UE all the while being compatible with regular Ethernet.
Qlogic was never really an Infiniband vendor --- their qib driver is still in the Linux codebase and essentially emulates verbs on top of a messaging-based design.