I'm not sure how other mastodon servers look, but this one is light years ahead of Twitter in terms of readability. I hope someone eventually writes a tell-all book about exactly what was wrong with that company and its approach to product design.
Different incentives. A publically traded corporation with thousands of workers trying to grow in perpetuity, has different goals than a community project. While the former has more resources, the latter is more mission driven.
That's default Mastodon styling "dark mode" and single-pane.
There's also a multi-pane "advanced view", similar to Tweetdeck, I'm told.
The dark mode is preferred by some but is absolute hell to read on an e-ink device. I have an outstanding issue request on that, as the theme cannot be changed if you're not logged in to a given instance.