Okay, My Own Private Idaho... WTF was that ending though?

Alright, so I finally watched My Own Private Idaho. Heard about it forever, mostly cuz of River Phoenix and the whole… atmosphere. I gotta say, the visuals were STUNNING. Seriously, that whole desert scene when Mike is having his narcoleptic episode? Felt like I was tripping with him. Gus Van Sant definitely knows how to create a mood. And River? Dude was heartbreakingly good. You could feel the pain and confusion radiating off him. But here's my question, and maybe I'm just too much of a simpleton action guy, but what's with the ending? Scott, after traveling all that way and seemingly caring about Mike, just goes back to his rich life and abandons him on the side of the road? Like, zero explanation? I get the whole rebellious phase coming to an end thing, but it felt so... abrupt. Was he ever really into Mike, or was it all just some kind of experiment for him? That always bugged me about the movie. It felt inconsistent with his character, even if he was a rich kid playing pretend. I know, I know, it's all about finding yourself and escaping your past or whatever. But still, even the coolest movies have things to question. Like, was that the same road Mike was on at the start, or a different road? Just the vagueness of it all kind of bugs me. Anyone else feel similarly? Or am I just missing some deep, artistic point?