$50 for the PHB, however, would be very foolish, unless the only intended audience is established D&D fans. (Heck, I am an established D&D fan, and that makes me balk.) And it'd be triply foolish if they also price the DMG and monster book at $50.
I'm hoping this is an error, though, and not their actual plans.
What I'm worried about is how much a $50 price tag would turn off people at brick-and-mortar retailers, like bookstores and game stores. And you need to reach new people at bookstores and game stores, if you want to keep the hobby alive in the long run. (We have yet to come up with a good way to market tabletop RPGs to new people online, so brick-and-mortar is still very important.)
A lot depends, of course, on whether you need the PHB to play, or if the Starter Set presents a complete game. If it's the former, this is a very bad move.
(Some have suggested this might be the price for some sort of premium release. That would also be better.)