1. 2 weeks ago I wrote a piece for US News on why I thought Bill O'Reilly would survive. The prediction turned out to be incorrect (we historians don't have great crystal balls), but in that piece I explained what it would take for O'Reilly to lose his show. That reasoning has held up very well. Fox made a business decision that keeping O'Reilly on the air promised to do more harm than good.
2. We're about to learn whether viewers tune in to Fox News for specific personalities or to hear a conservative slant on the news of the day. If it's the former, Fox could be in for some rough sledding ahead. In the last 6 months, they've now lost their 7, 8, and 9 PM hosts, to go with the network's mastermind, Roger Ailes, getting forced aside last summer. If Fox remains wildly successful ratings wise, it will be a sign that their personalities are basically interchangeable. The audience tunes in for a specific perspective, and to see their worldview applied to the stories making headlines. They want to see liberals pummeled, and conservatism championed. Who exactly provides this content matters less than the content itself.
But O'Reilly's departure could create an opening for one of the various upstart conservative broadcasters, be it CRTV, Newsmax, etc. With Fox losing (or jettisoning in O'Reilly's case) their entire primetime lineup, conservative Fox viewers might be more willing to give other outlets a chance than they have been in the past. That's likely one reason why Fox is relying on promoting from within to fill the vacancies—they want to provide their audience with familiar faces and programs in an effort to mitigate any damage done to their ratings.
3. What becomes of Bill O'Reilly? One option would be to head into semi-retirement. Instead of the grind of doing a daily show, O'Reilly could continue his wildly successful book franchise and otherwise focus on enjoying life. But for a pugilist like O'Reilly, he doesn't seem like the fade into the sunset in disgrace or under a cloud of suspicion type. And most of his fans likely believe that their favorite host has gotten railroaded by a combination of the liberal media, liberal interest groups, and sniveling, spineless Fox executives. So it's easy to envision O'Reilly wanting to author one final chapter in his media life—a sort of FU to his critics and to the Fox executives who refused to stand behind him.
If he chooses that route, the best fit for O'Reilly moving forward would likely be a subscription based operation. Such a business model provides far more protection for employing a popular, but controversial, personality. Advertiser boycotts matter little when subscription fees drive the profitability of a media outlet. O'Reilly could start his own platform or he could migrate to a preexisting outlet, be it CRTV, the Blaze, Sirius/XM, etc. But such a future would allow him to remain profitable so long as his fans remain loyal. The opinions of non-fans would matter little.
Such a business model has allowed Howard Stern to remain successful on Sirius/XM without the hassle of worrying about potential FCC fines, angsty station executives, and advertiser boycotts sparked by protestors.