Or you know it is because WoW stories move at very glacial paces. It took 3 expansions before the draenei became relevant again(then boom, two whole excpansions that had plenty of draenei content, and then nothing again thus far). The worgen at the very least have gotten some screentime in Legion and BfA due to Genn/the faction conflict.
Heck, the gnomes still don’t have their city.