Tangent topic; I have often wondered if back pain was less likely in the past? How did they manage without chiropractors?
Chiropractors are charlatans so it was the same as any other healing elixir scam that was being run (which are notable and commonplace throughout history).
My brother is a chiropractor who mostly agrees with you. He thinks that most chiropractors do about as much harm as good, or more.
Of course, he believes otherwise about his own particular school of chiropractic, the Gonstead Technique. As a long time beneficiary of that method I've come to agree with him. It has helped me quite a bit, and the long list of his vastly improved patients (many or most who are refugees from other chiropractors) is impressive and convincing to me.
Some healers are quacks; in some disciplines, most are. But that doesn't make them all quacks.