In my opinion, it had a lot to do with her pregnancy, new image, and Super Bowl & Inauguration performances.

The public has been watching Bey grow since she was in her late teens and have been anticipating her and Jay having a baby since B'Day. A lot of the respect and adoration people have for Bey, outside of her work, comes from the fact that Jay loves her as much as he does and isn't afraid to boast about it. People love their love and because they 100% respect each other, and have the friends in such high places, it's kinda hard for people to knock them. I mean, liking/loving/supporting them it's kinda like the "cool" thing to do now.

I also think her instagram, tumblr, website and the overall carful handling of her current image played a huge part. She's not as... inauthentic as she once appeared. She and her team have been sure to avoid as much negativity as possible by highlighting all the great moments of her career/personal life. she hasn't allowed the release of anything that can be seen as negative or unflattering chip away from her overall being. I mean, her team was even trying to pull the pictures of her crazy faces from the Super Bowl. It can be see as narcissistic and too thought out, but it's smart.

As for her career, her '4' album did good enough. It wasn't a major success, but it wasn't a total disappointment in the area of album sales and singles performance. and her having a baby mid-release saved it, because no one really cared (I'm talking GP, I know the fans did) about the album anymore, it was "OMG! she's pregnant. Is the belly real? etc." And her tour is doing wonderfully, but that shouldn't be a surprise since she hasn't toured since 2009. and she's released quite a bit of material since then and she's a great performer w/ an extensive catalog.

Beyonce does not flop.