I see the same thing with, say, BBC News. 40 million (!) followers - and their posts rarely get above 100k impressions.
Traffic appears to have cratered across Twitter. On the rare occasion I post there, I hardly get any interaction. A year ago it was still a significant driver of traffic. Nowadays, nothing.
But now every post by these same politicians gets tens of blue checked trolls spewing hate. So the politicians take breaks, post less, or ignore comments, and are thus less accessible for those of us that were respectful.
Unfortunately there is no new winner. Some have moved to mastodon. In my circles mostly to bluesky. But there is no way to have the same reach at the moment.