I think it's hard to discern cause from effect, but I suspect the glorification of victimhood might be the driving factor. Nowadays, victimhood grants you clout - which makes me wonder if people over-report their mental health problems.

Otherwise, though, I actually see therapy as filling a very similar role as religion historically has. Think how similar a therapy session is to a confessional.

And so insofar as therapy represents a secular version of confessional, I think it represents an improvement over how we dealt with mental health in the past.

That said, therapy today can vary a lot. When done right, good therapy is largely an opportunity for someone who has a lot of bad philosophy to have their harmful myths dispelled by a better mental model. But many therapists are bad philosophers, and the mental models they offer their patients are not very good.

As therapy starts to normalize towards more solid philosophies (which I think / hope it will over time), therapy's effect on people will get better.