I changed my main from a tank to a DPS because the obsession with tank dps in this game has made end-game tanking just a DPS role with low numbers. Might as well play real DPS jobs.
IMO there's probably many "old school" tanks who have stopped tanking in FFXIV for a similar reason. Not that I'm demanding a change. That's just how tanking is designed in this game, so people who don't like it go, and people who like it pick it up. If it was the other way round, there would still be a lack of tanks.