I think a big part of it though isn't so much that people who play healer are just bad, but that XIV's extreme reluctance to dish out the amount of damage needed to warrant the shear amount of healing tools we have has left healers unprepared to handle them effectively. And the problem is that SE will likely see this stress and then dial it back for the remaining raids. Then they'll go "well we tried to make fights deal more damage but everyone complained."

They need to keep this threshold of damage consistent and trickle that down into more casual content (by which I mean, introduce things like bleedbusters and double raidwides that can still be easier to manage in casual content, but gets people in the mindset of expecting that kind of heal check.) Over time, people will get better. At a certain point, you need to remove the training wheels, and just because your healer-child falls doesn't mean it's time to screw the training wheels back on. You have to let people fall if you want them to learn.