That's because it was optimised to show you ads, and not for your comfort. Otherwise it wouldn't be a ridiculously bloated SPA, and instead be more like Nitter or some of the other alternate UIs that have appeared. Given the focus on $$$, I doubt Musk will change that aspect of Twitter in a direction that's better for you.
Definitely, platforms optimize for ads. But these things are actually not concerning ad display/engagement. On the contrary, these UX improvements would increase my engagement, and thus ad engagement.
