Not exactly, since people who do NOT vote never get tallied in the exit polls.
But they don't show up in the "real" polls, either ;-)
Just buzz I've picked up: not rigorous.
I think it was a combination of things. The Republicans upset the fiscal conservatives by spending money to try and buy votes. They've always run against big spending Dems, but when in control of all three branches, spent more than the Dems. They seriously hurt themselves on border security, by not addressing it before it was a major hot button.
However, this is probably an historical trend that is in line with normal six year Presidential cycles. We'll survive.