California
Texas
Florida
New York
Pennsylvania
Ohio
Illinois
Georgia
North Carolina
Michigan
Which major industry unites them? Which major industries are not represented? You have tech, finance, automakers, agriculture, tourism, and oil. Maybe not much mining and fishing? Probably something else, but these are very different states.It's also worth noting the math really doesn't work out, the electoral college makes it easier to win the whole thing while carrying less states/votes (Which really shouldn't be surprising). With both the popular vote and the electoral college, you only have to take the 10 most populous states to win the whole thing. But the difference is that, with the current electoral college you generally only need to get 51% of the vote to win the whole state, which is significantly easier and turns states like California from a 60% to a 100%. With the popular vote, to actually win in that fashion you would have to take almost every vote in those states, which is practically impossible considering the diversity.
Totally different dynamic than general elections, which happen all at once rather than different dates in different states.