Because people are super reactionary, turn any playoff loss into a referendum and love the idea of teams being "solved."
Full disclosure I thought the Ravens and Patriots were a bit overrated before either of these games. Patriots offense looked bad for 3 months and the Ravens were always susceptible to needing to make a comeback and having the wheels come off. Playing from behind is the antitheses of how the team is built (the 49ers have the same problem, btw). That said I just think the Titans executed their gameplan to perfection the last few weeks. Get a lead, play ball control offense through Henry and see what happens.
Before the playoffs I pegged the Chiefs as favorites in the AFC. NFC I liked the Saints so that obviously flopped.
Going forward I think the 49ers and Chiefs are overwhelming favorites to reach the SB. I'm excited to see how it all plays out.