Do you never go to a dentist because you can never be sure they're fixing your teeth? You don't know if they're superficially treating your teeth just enough to warrant another visit instead of "fixing" them once and for all.
Do you never hire an engineer onto your team at work? You can never be sure if they're putting bugs into their code on purpose for job security.
I mean if you take this kind of thinking to its logical conclusion, it gets pretty ridiculous.
In any case, "be skeptical to some extent, but don't be _scared_" seems like a good middle ground in this debate.
Some dentists even had their contracts changed to encourage them away from the practice.
https://healthmedia.blog.gov.uk/2016/11/14/drill-and-fill-cu...
Realistically, blind faith in professionals is as unrealistic as blind paranoia.
I don't think it's possible to say "Of course we should trust psychiatrists" in one sentence and then add "But of course we don't really know much about mental illness anyway" in the next. The reality is that pharma in general has a mixed reputation, and psychiatric drug treatments have a very spotty scientific record - as do the various kinds of talking cure.
Psychiatrists probably won't encourage session dependency, but psychotherapists might - especially in countries where you can hang out a shingle with no training or background at all.
Getting help for difficult personal and emotional issues can be a minefield, with minimal consumer protection. You literally have more guarantees that your toaster is going to work as advertised.
Shady dentists performing unnecessary procedures so they can rip off their patients is a rare but serious problem.
Do go to a dentist when you have a clear problem you know about, and do go to the dentist from time to time for routine checkups / cleanings, but be careful about choosing a dentist and skeptical when a new dentist suggests your apparently healthy teeth actually need extensive work.
I've never had a therapist bat an eye when I tell them I'm doing well and I don't need to come in for a while. My last therapist went on maternity leave and recommended me to a colleague who they thought I might enjoy working with. It's been great and I'm not going back to see my original therapist. I guess they should've sent me to a bad therapist so that I would come back and be their client again, but the person they recommended me to is great.