I personally can name about two dozen people I know in WA state that just didn’t vote for president at all since they knew King, Snohomish, and Pierce counties would decide the state electoral vote and that all would go to Clinton (same thing for senate). So instead, they skipped and voted down the ballot. I suspect there are A LOT of people in NY, CA, MA, and other heavily blue states that did the same, or voted 3rd party. And I’m sure that’s the case in heavily red states as well, with several Clinton supporters standing silently by.
But I do think the number of people in blue states that refused to vote or voted 3rd party knowing Clinton would win greatly outnumber the number of people in red states that refused to vote or voted 3rd party knowing Trump would win. It is in this margin that I think the popular vote margin disappears. But I can’t prove that.
Further, when talking about popular vote, these numbers are percentages of either voting age (53%) or voting eligible (can’t find the number). I haven’t seen a thing about registered voter turnout. But regardless, it is does not follow that earning 50+% of the popular vote indicates any sort of mandate for the remaining 47% that did not vote. The popular vote is not only meaningless with respect to the legal outcome, but also in terms of mandate. For my part, I think the elections for the house seats speak more about what the country as a whole wants, than what the popular vote says.