I have had success with join up in the past, but it is not the only way to initiate a bond/respect with your horse (and I wouldn't recommend it as the only way). Having said that, its not something that can be learned from reading or watching videos. I had done a ton of research on it when I had my first horse, but when I tried it with her it was the "predator" scenario where she just ran and ran, so I obviously didn't know what I was doing. I then contacted an experienced horse person and learnt from them from watching them work with their horse (so maybe this is an option you could try). I think its essential to understand exactly what's going on and equally important, the timing of it.
For me "join-up" translates to a variety of other methods and situations. My gelding would always walk up to me in the pasture to get caught (once I was in the 20ft range), however the odd time he wouldn't come in. I would ask him to come in and if he chose not to, he had to work. I would immediately take up an aggressive stance and chase him away (and this is in a field). I would also make him turn before he got to the other horses/hay, so he would be trotting around alone. I would then invite him in again and 9/10 times he would happily trot over to be haltered (if he just stood, I would make him move his feet again). This scenario is very much like join-up to me, as he had to choose to come in (he wasn't working super hard or dripping with sweat, he would trot for maybe 2 mins). So I do find merit in the join-up technique (as it is has pressure/release principles, or at least that's how I do it), but you need someone who has experience with it to help you understand how/why to do it. Even though join-up has worked for me, its not the only tool in the toolbelt :)