Yes, and I spent most of my life (until I got up and emigrated) in the one-party rule that was (and sadly remains) Republican Texas. The avowed goal of Texas Republicans (and they have nearly succeeded) is to wipe out any other party. There are a few Democrats left, and Beto O’Rourke was able to help some state rep seats go Dem, but the Texas GOP still has a super majority in both houses, every state-wide office, and the courts.
I’ve seen what one-party rule looks like, and I do not support it. I believe in loyal opposition parties. I believe in factionalism (which is to liberty what air is to fire, as Madison said). I believe in divided government. Absolute power corrupts absolutely.
I believe some Dem leaders (no one actually says Demo, btw, that’s not a diminutive used in American politics) are greedy for power and money. I believe the internal mechanics of the party and the primary system (remember, every Democratic voter has a say in the party selection process AND can come to precinct meetings, county conventions, state conventions, the national convention, take on leadership roles in the party etc if they want, most just do not) ultimately make this harder and harder. We’ve managed to unseat some pretty entrenched and questionable members of our party in the primary process. And you can expect more of that as our leadership continues to skew younger, less white, more queer, more female etc. Unlike the other party which continues to skew older, whiter, and more male.
I’ve voted for Green candidates and Libertarian candidates in races where a Democrat wasn’t running. I would gladly see Congress move to a Coalition, power sharing arrangement with loyal opposition parties and more independents. Bernie is an independent, technically. As is Angus King. Gary Johnson is a libertarian, and I agree with him half of the time, he governed as a Republican, but only in name only. Everyone knew he was a Libertarian. Jesse Ventura was a great independent governor.
The majority of Republicans have no moral authority and are not loyal to democratic (lowercase d) or republican (lower case r) ideals. They must be run out of office, and I think Dems are the best shot for this, but I’ll gladly work with any other reasonable, mainstream party in American politics (we actually are a multi-party system on paper, but we need to do more to bolster the other parties) to see it happen.
Edit: further clarification about how leadership works in the Democratic Party. There are positions from precinct captain all the way up to the Chair of the Democratic National Committee. The highest positions are contested, but lower positions almost are never contested. Every Democratic voter can contest these party positions. Every single one. You do not need to be chosen, you do not need to donate to the party, you just need to show up. If you don’t like the leadership at the top, you gotta show up at the bottom. That’s what I did. I technically had an opponent, she never actually showed up after putting her hat in the ring. She lost, by a landslide. I may as well of not had an opponent. This is disappointing. Democracy is not a spectator sport.