So, I suspect the key to your experience is buried in this sentence: "I do follow politics pretty closely, and it seems relatively balanced overall."

Balance doesn't mean much by itself. Doesn't mean "informative" or even "accurate". Extremists from every walk of life screaming at each other might be in balance, but isn't much fun to be around. Note that the person you're replying to didn't even mention politics as such, much less a lack of "balance".

I watched twitter for years, starting in 2007. It was never what I'd call "good", but for quite a lot of years you could reasonably use it to follow people or topics that interested you without consuming an inordinate amount of time or attention. In fact, for most of its history you could do this without even bothering to log in - for a long time, that made it fairly useful as sort of an alert system. And that is long gone, so gone there's a good chance most folks using it now don't even remember (or never knew) that was ever a draw.

What's left is people who are logged in, _engaging_. And man, that was always the worst part of Twitter, the constant posturing and troll-baiting for clicks, pushing every viewpoint toward its extreme.