I'm not saying that they will work. But acupuncture and yoga are not the same as pixie dust, dung pills or what have you.
To give an example of what I mean: the waters of the Ganges were said to have "magical powers that cured disease"[0]. It was later found that the waters contained bacteriophages that killed bacteria. Could anyone have guessed this?
Okay, so why don't they show any efficacy above pixie dust in double-blinded studies?
It's all deeply frustrating. I tried acupuncture a few years ago (at a doctor's recommendation) and did a lot of reading. It didn't work for me, unsurprisingly - about the only thing it's been shown to have any effect for is some types of lower back pain, and my pain was (is) mostly in my hands.
It doesn't seem completely impossible. You could have someone put the same needles in randomly, instead of in whatever location acupuncture claims they should be put in.
Therefore single-blind studies of acupuncture are trivial; just find people who don't know where the needles are supposed to go. A double-blind study could be possible, if you trained two sets of people to perform the procedure (one incorrectly).
This study introduces them and shows that acupuncturists can't well distinguish both types: https://www.biomedcentral.com/1472-6882/7/31
This study uses them to check for differences in pain-relief (there are no differences): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2765771/
Chiropractor: "Great! Now let's just get you scheduled for three appointments a week for the rest of your life."
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... :]
Depends what happens next.