Well, i think this comes down to the % of therapists that you think are quacks. I say this because if you think 50% of all therapist are no good for you, then the probability that, after seeing 8 others, that this guy is also not for you is quite small.

There would likely be another factor at play. One thing that is unchanging across all the therapists you've seen is you. You might not be ready for therapy, or open to the experience. It's very hard to give someone something they don't want to own. Perhaps you therapist shopping in order to demonstrate to yourself and your old therapist that you are in control. A kind of replaying an old scenario over and over, but with a different ending in which you "win".

However, if you think 90% of therapists are idiots, then, yeah, it's probably time to resolve yourself to a lot more shopping.

Clearly the therapist plays a role in the progress of therapy. There are 2 people in that room though. As the adage inducates "when the student is ready, the master will appear."