I have never participated in a presidential election that wasn't "VOTE BLUE OR ELSE!" And it's never going to be any different.
There's your problem, I think. If all you do is vote for president every four years then it's gonna be deeply unsatisfying, and the level of actual impact you're gonna be able to have on the system (especially as a left wing person) is gonna be pretty much nonexistent.
I think working for the pres campaign of someone you really believe in (Bernie Sanders from back in the day, some local school board, maybe like a state congressional seat) might be more satisfying. And there are plenty of people who are working for positive change outside of just showing up periodically to vote for which corporate candidate, and sometimes they get big wins.
I think it's easier to make change on a local level than on a national level and definitely than on a presidential-election level. But yeah, I feel you on this. I'm just saying that change is possible. I mean... weed is legal now in a bunch of places. When I was growing up people still sometimes went to prison for a long long time for that shit. It never made any sense, and everyone knew the system was busted, but nothing ever changed for decades and decades, until one day, hey! It did.