The power of controlling information marketplaces.

Also I suppose it’s crucial to point out that it’s not just controlling the marketplace for news, it also needed one party to be absolutely focused only on winning elections, and eschewing bipartisanship.

Yes and no: nowadays third-parties can steer the people demands themselves. It became much easier with internet and "web brigades" (recently started utilizing AI as well).

So on one side yes, people demanded it. But on the other side, they were manipulated to think one issue is more important than the other, to think that "the whole system is broken" etc.