A lot of this reflects a shift in the mindset of MMOs.

Historically, tanking was your most valued role. You had one MT for your 40 person group, and they had to be your most reliable and most geared player. If you failed the mitigation check, you failed the fight.

Tanking is also the most interconnected role in the trinity. Because what you do impacts everyone in the group, your success depends on how you interact with and read/meet the needs of your teammates. It requires a decent amount of social intelligence.

Modern MMOs have realised two things: first, that the average player who pays your sub plays dps, and second, players paradoxically often don't have time for social interactions and prefer to treat this like a massively multiplayer single player game. DPS is the best role to do this with. LFG and jump into a group of 7 faceless players, maximise your dps output, and shout and scream at anyone who dares to invade your single player game filled with single player expectations. Who needs a community?

That's why we've seen a switch. Gear goes to dps first. New jobs? We don't have time to make a new healer, we need more dps. There are three different dps "roles", in contrast to one tank group and one healer group. That's also why it's now relatively rare to see an actual "tanking check" or "healing check", simply because four out of the eight players have neither the patience nor the tolerance to wait around with progression through that. And dps numbers are now very deliberately inflated so that a skilled tank or healer generally isn't going to accidentally embarrass an under-performing dps player.

At the end of the day, though, you can't change the fact that MMO trinities intrinsically have more responsibility and teamwork built into tanking and healing. So the next time you find yourself on a dps job preening over your artificially inflated damage numbers, find yourself backseat tanking, or find yourself complaining about the lack of adequate healing as you deliberately fail mechanics to get off more GCDs to compensate for otherwise terrible uptime, remember this: your tank and your healer knows full well that they can kill you at any time, and they're probably fantasising about it as we speak.

I mean, we love you, you single-handedly carry the team, and you're entitled to first pick on all the weapon drops.