I think each feeds the other. You're right that news orgs that have fed readers' desire for bias-affirming content have done better than those that still aim,

I think each feeds the other. You're right that news orgs that have fed readers' desire for bias-affirming content have done better than those that still aim, however imperfectly, to present the news objectively. But those news orgs wouldn't thrive if not for demand, and there is quite a lot of social science research out there showing that while most people _say_ they want unbiased news, their actual consumption habits indicate a preference for news that is in line with their existing ideological bents.