There are maybe 8% undecided voters right now, and since they are the most uninvolved and apathetic voters out there, maybe 3% will eventually vote. And the only ones that matter are in the swing states.
So what do these undecideds never, ever pay attention to? Meet the Press, Fox News, MSNBC, and all the other political talk. And they will never in history watch a press conference, watch clips, or read up on one later.
Who do they pay attention to? Howard Stern, The View, Jimmy Kimmel, Colbert, 60 Minutes, Oprah, and so on. And in many instances, a popular podcast will reach a lot more target voters than all of the political talk shows and press conferences combined. And massive, boisterous campaign rallies - where no one leaves early - generate lots of local (swing state) positive news coverage (and volunteers!).
So when they ask: wHy Won'T kAmAla dO iNteRViEws wiTH (fill in the blank)?
Because she's playing to win.