Compare to a lifetime on SSRI medication, or untreated depression, or PTSD. Etc. Etc. On aggregate, people are aware of the difficulties that come with psychedelics and still chose to go through, because the known alternative is in fact much scarier.

Also, I think a lot of the persistant issues people are experiencing are due do the still marginal status of these interventions in our society, where it's still not so common to find people who've been through it for guidance.

What does it mean to have a "bad trip to the dentist"? A dentist can also cause decades of discomfort, but most trips (both drugs and dentists) turn out great!