Why is the healer class basically a one spell dps class?

[Semirhage]

There will always be a relative shortage of tanks and healers. These are team-focused support roles. People pick these roles so that they can have an impact.

You don't need incentives to get people to play DPS. There's just less hassle, and you can play it like it's a single player game. The problem is that because the majority of the playerbase plays DPS, that's where the majority of the focus and effort goes. You want to have impact? Play DPS. You want to have first dibs on gear upgrades? Play DPS. You want job variety? Play DPS.

You're not really giving up that much control over how the fight pans out, either. Bosses move and position themselves, so tanks don't really tank anything. Outgoing damage completely scripted, so your healers aren't reacting and making critical saves so much as they are following a set of timestamps. Anything interesting in gameplay just comes down to dps, and as we've seen in the past two expansions, there's a widening gulf between 'support' roles and the main stars of the show. Why wouldn't you play DPS? It seems obvious, in retrospect.

Tangent supporting point: I played a terrible pay to win MMO long ago that followed this pattern exactly. As time moved forward, classes became stronger and less reliant on one another. You could play it like a single player game for the most part. Shockingly, it meant fewer people played tanks or healers. The problem here is that healers could heal through harder stuff and had 6+ massive stat buffs that lasted half an hour that provided a significant boost to performance. Players started to complain that they couldn't get steady access to healer buffs or a healslave. They had to roll alts and level them up just so they could log, buff a friend, then have that friend do the same. The solution? The game added pets with more powerful heal spells than the healer classes and dropped NPCs in major towns that would just put all of the support class buffs on you for a minimal fee. No I'm not kidding. To hell with making healers and tanks relevant or fun to play, just reduce their jobs to NPCs. Trusts are a less-offensive extension of the same thing after all.

DPS are always center stage in the end.