Orgasms happen in the brain. You can do stuff with the body and it's cool but there's no scientific basis to the idea that stimulating the genitals or anywhere else directly causes a buildup of prolactin in synaptic vesicles. Every signal coming from the body is heavily processed and translated.
The best guess I can come up with, which has almost always been supported by my experience, is that it's really the intensity and duration of arousal, not stimulation per se, that leads to a stronger orgasm. Therefore, if you take up edging, or anything else, because you think it will get you off, but you don't actually find it sexy, you will probably get bored and find it doesn't work as well after a while.