All relative. You don't think my guys would spend more time in Alabama, Mississippi, etc? How many people stay home in red states thinking their vote is worthless? Would balance out their counterparts in blue states.
No they wouldn't spend any time in states that didn't have enough of a population to affect the outcome of the election.
Lots of people stay home all across the country. Our voter turnout has traditionally been among the worst in the industrialized world.
Still, if we had an actual popular vote contest, it really would be decided by a handful of states. California, Florida, Texas, and New York have a population of over 100 million people.
Overall, people almost always misuse the "[insert candidate] won the popular vote." It's really a misnomer.