Lazy Healers In Parties of Eight

[Exodyce]

All healers are now DPS with a utility of healing... This is because they made it easier to dps by removing Cleric stance and all of the healer npcs are shown doing dps.
... adapt and get your numbers up or bow out of the role.
For those who think I’m being harsh, I loved pure healing and dislike doing dps on healer but I have accepted the change in game design and moved on from healing.

I'm not sure this is the reason. I think it is much more based on the population of this game growing and more people realizing how much time healers actually have to DPS. In 2.X, SCH had something like 5 dots and did 80 percent of a DPS's damage. Also, Eos was stronger back then. Now, healers should generally do about as much combined damage as your lowest dps, but that's just for progression. If anything, there was more incentive to dps as a healer before because you could do relatively higher dps.