I think I meant to write a couple lines at first but the text just kept increasing and then I went into notepad to really put a spin on it. Oops.
I can't say for the whole psychedelic using population what their motivations are but as far as I can tell there is a clear distinction between users who are doing spiritual practices or trying to find meaning in their lives and so on versus slamming the heroin needle or hitting the crack pipe to get the craziest dopamine rushes you have ever experienced. Not to mention the latest meme to hit the mainstream, the microdosers, who use it as performance enhancer.
Psychedelics as a broad group of chemicals all with similar action in the brain and body contribute to thinking patterns and removing filters on your consciousness. Some people find after one or more trips that they've uncovered something that gave them a new lease on life or something. Some junkies who 'take anything they can get' even avoid psychedelics because it puts into focus the state they are in. They don't want to face that for whatever reason. Maybe that's why they are there in the first place.
One meme in the psychedelic culture goes "when you get the message hang up the phone". You don't need all the pleasures in the world. You certainly don't need to get those huge dopamine rushes daily and you don't need to or likely want to keep constantly tripping in search of the craziest visions and highest peaks, especially if you don't take the hint and start working on bettering your 'sober' self.
Of course there is a whole scale of motivations in between and it's reasonable to except people can function in society despite occasionally using catalysts to trigger pleasurable experiences, as long as their whole existence does not become only that at the expense of maintenance. There is some science on that when your other needs are covered and you're doing pretty well you don't end up in a downward spiral like that and won't get addicted or at least not in the same proportion as when you're trying to fill a void with external catalyst induced neurotransmitter rushes.
I'm not the one to overtly preach or advertise indiscriminant psychedelics use because they can reveal or really put into focus all the bad shit you've been avoiding or traumas you have pushed deep down that you kinda forgot they existed or never dealt with. If you're unprepared or already on the edge bad trips might push you past it and you may end up with something that seems like permanent mental problems. Instead of increased clarity and awareness you may end up at least temporarily in the shitter, and if you have no coping mechanisms you could be fucked.
In my experience I think they contributed to giving me an ability to 'see beyond' the every day reality and from that the motivation to really pay attention to and hone the way I live and act towards myself and others. It's as if for a long time I was a hostage to the depression in this body and couldn't take the steps to fixing the situation back when it was less dire. I used to hit the bong every day all day and slowly cause ruin to my body in many other ways. I became more aware of what I was doing wrong and where my anxiety was coming from.