I think deep down he was frustrated that his hands were tied from enacting more progressive policies

Ultimately, I cannot know what was going on in his mind, so we are theorizing. But here's my counter-theory. He was frustrated because he believed in bipartisanship, in both parties working together for a better country despite neither getting everything it wanted, and he discovered the other side would literally burn the country down for an edge. I think he was an idealist, but his ideal was "one country, one people" instead of this Plymouth/Jamestown contrast we still seem to represent. To that end, he was willing to sacrifice almost anything, and only started playing hardball when he realized after he gave EVERYTHING, the other side smiled and said "so we're going to vote against that".

MAYBE passion like mine has driven them away, but let’s be honest, there’s a reason the crazy uncle who listens to Limbaugh or the latest charlatan runs their mouth and everyone else remains quiet. The loud mouth gets their voice heard and to the detriment of the country, that’s influential.

You're not wrong. I don't like that we can't have successful left-loudmouths. I like to say/think it's because a large part of the Democratic base is interested in truth and facts, but that doesn't explain the lazy people who are willing to allow for alt-right nonsense but not leftist discussion.

there has been no progress on abortion and Republicans have only continued to cripple LGBTQ rights as well as obstruct tuition forgiveness

I used to think that Roe being overturned would be the last nail, that Red states would spontaneously turn Blue from people who suddenly realized they were in Gilead. I used to actually think they wouldn't let their best tool to rally the alt-right go away. And I was right that it hurt them now that people are living in the hell of abortion being illegal, but it hasn't been the wave I expected. I really hope you're right, but look at Texas. It was supposed to be purple already, and quickly turning Blue in the next 20 years. And that was before Dobbs. I just don't see that motion yet. I hope to see it soon.

Overall I view Trump supporters as a lost cause, and I literally cannot count more than 2 people I know who regretted their support for Trump since 2015.

Sad, but true. I swear, there's a mile-long list for why the Republican party should be failing. And they KNOW it. They hate Trump as much as we do. Coming in to 2016, Republicans were internally talking about looking more moderate because they were afraid they'd alienated too many people. Trump wasn't supposed to have a chance in the Primary. They're like a zombie party. Things that would destroy almost any other party in the world are reinvigorating them. Non-stop sex scandals? MORE VOTES.