The problem with the National Popular Vote Compact is irrelevant. If enough states "ratified" the NPVC, they would already be sufficiently blue enough that it wouldn't matter if the Compact were ratified or not; they would most probably get at least 300 electoral votes in non-competitive states, well over the current threshold of 270, without need of the Popular Vote threshold. But if the country were at a point where NPVC was passed with states totaling 270 votes, we are well past the breaking point, and well on the way to a Soviet dystopia anyway, if not already there.
FWIW, I wrote a piece on RedState about the NPVC back in 2016:
They have already indicated they will get rid of the fillibuster. Add to that they are going to make DC and Puerto Rico states, that gives them 4 more senators. Without the fillibuster, all they need is a simple majority to pass anything - which they will have. They will move to eliminate the electoral college. They won't have to worry about doing anything unconstitutional because they have indicated they ae going to expand the supreme court and pack it with lefty justices who will rubber stamp anything they do.