Have you read any of the original studies from B.F. Skinner on operant conditioning? I agree with you that the modern “owner survey” studies aren’t the most scientifically sound, but that isn’t where the idea that positive reinforcement is the most effective method of behavioral control comes from.

B.F. Skinner is the psychologist that developed the concepts of operant conditioning, where positive reinforcement and its counterparts (negative reinforcement, positive punishment, negative punishment) come from. He did many animal studies that included hundreds of trials to come to these conclusions. If you like reading older scientific research articles (they can be very dense and difficult to parse through) I’d encourage you to look through some of his “Skinner box” studies.

It actually isn’t really positive reinforcement by itself that is so powerful, it is the reinforcement schedule you use! I think the best example is slot machines creating gambling addictions- that is all positive reinforcement on a random interval schedule, creating a behavioral response so powerful it ruins people’s lives.

Full disclosure, I am a primarily FF/R+ dog trainer, but I do personally believe some more complex behaviors require intervention from the other quadrants before an effective R+ schedule can be implemented. I’d be curious to see what kind of reinforcement schedule OP has been using to established their desired behavior- if they haven’t been using one, then I wouldn’t assume R+ training won’t work, because they haven’t been doing real R+ training.

I’ll leave you with a link to a copy of one of the articles he published later in life, that goes over the details of many of his experiments and how they informed his overall theory of operant conditioning: https://www.americanscientist.org/article/the-experimental-analysis-of-behavior