While there is a part of chiropractic that is, imo, alchemy,
don't disregard the rest.
The chiropractor I went to was in a fairly wealthy neighborhood, had a nice office, and seemed "respectable." However, once he actually started, it very quickly became clear he hadn't the faintest clue what he was doing, didn't care much, and was just going through some very simplistic motions. He not only failed to have any effect on my problem, but he was singularly ineffective in even trying to track down the issue. It was a very different experience from a normal doctor: almost every real doctor, even when completely confused and out of his depth, at least has clear techniques for probing and trying to figure out what's up or at least figure out the next step to take or who to ask—and they will very freely refer you to someone else if that's called for. This chiropractor: nothing. Zero. Nada.
After 30 minutes of painfully obvious hand waving, he then said "ok, well I guess you'd better schedule another appointment." I then went out into his waiting room, and heard another patient chatting with the secretary, and it became clear this patient was a "regular."
It seemed fairly obvious that the whole scam was to get patients on the appointment treadmill, offering promises, but no relief, continually dangling in front of them the hope that "next time" things would get better...
Maybe not every chiropractor is this way, but my experience perfectly matched their generally poor reputation, so I suspect it's more common than not.
[I didn't schedule another appointment... :]