The real question should be "What happened to the election?"
The #1 story on the evening news on every network tomorrow should be "The election: what went wrong?" In every other country in the world, this would be considered a sign that the election was stolen.
Stolen?
R+7 or even R+8 was reasonable given the polling. R+9 wasn't out of the realm of possibility. North Carolina slightly favored Hagan. The Roberts/Orman race was a flip.
The governor's races had like six races that were basic coin flips.
There wasn't enough reliable polling in the House to really figure out much of anything.
The races that were completely blown were in Maryland and Virginia and to a lesser extent Kansas. Aside of that, it's just error on the fringes of a predetermined result.
A few point bias can make quite a difference, obviously. But stolen? Very unlikely.