Any time a candidate wins the electoral college vote but loses the popular vote, the electoral college is pointed to as being flawed. The popular vote is much easier to win than the electoral college vote. Candidates focus their resources on the electoral college because that is what is required to win.
In the election just finished, Trump put no resources into California. If he was trying to win the popular vote, he would have poured dollars into California. He probably would have lost the state still but his popular vote would have increased.
Overall, it would be easier to find a strategy for winning the popular vote, if that was what it took to get elected.