> Elections would just switch from swing states to appealing to California and Texas if we did everything with purely popular votes.

I don't see why that would be the case. To win an election you don't need to win states at all; you need to win lots of voters, and those voters could come from anywhere.

You could lose every single voter in both CA and TX and still win the election, given different political demographics across states.

As an aside, I also think abolishing the Electoral College and going strictly by the national popular vote would increase voter turnout for presidential elections. I live in a solidly blue state, and if I didn't care about down-ballot races, I probably wouldn't bother to vote in presidential elections, since my vote doesn't really matter here. Only votes in swing states matter under the current system.