The question was, “what games popularized certain mechanics.” The question was not, “what games created or introduced certain mechanics.”

Yes, there were other MMOs before WoW, but WoW took MMOs to a completely new level of popularity. I didn’t play ANY MMOs before WoW and wasn’t really interested to, but it was so popular that I jumped on to see what the deal was. Since then I have played ESO, LOTRO, AOC, and one other whose name I forget.

Other MMOs were popular among gaming nerds before WoW, but WoW made MMOs popular to normal people.