Nowadays the states are too locked and set in their ways compared to a generation ago. No I don't see it happening. First of all, Republicans would have to lose even Utah and Wyoming. Even back in the 70's and 80's this wasn't possible for a Republican to lose so badly. Democrats too would have to lose Vermont. I'm assuming we're still giving them D.C. which isn't being included in this sweep.
Every presidential election won by the Republican Party specifically during the 1970s and 1980s were 40-plus-state landslides. The one losing election, in 1976, saw the unseated (and never elected) Gerald Ford hold 27 of the 49 states which carried four years earlier for the re-election of Richard Nixon. It's one of two presidential elections in which an outright winner carried less than 50 percent of the nation's participating states.
What I meant by my wording was that in the 70's and 80's states weren't as set in their ways. We're living in an era of closer elections. Our last 6 have been competitive historically, especially 3 of the last 4.
