>>39433377You could say my reasons are headcanon, but it's common enough that enough people believe it and I believe it too.
Red becomes the Kanto champion, but afterwards gets overwhelmed with stress of the title, he just wants to train Pokemon. To get away from everything he secludes himself on a mountain for a few years. Eventually Gold defeats him, and I'd like to think that's where he comes back around and realizes he should get back to civilization (as seen by his return in BW2). He reunites with everyone and continues on training Pokemon, regardless if he's not the best anymore, because it's what he loves doing.
