The national POLLS had Clinton ahead by an average of 3%. The final margin for Clinton in the popular vote was 2.2%.
Are you suggesting that there were lots of polls that polled all the states (or at least all the close states) and among them only predicted that Trump would win the electoral vote?
Many, many polls were a couple of weeks old. Lots happened in the last two weeks. Polls are relatively accurate within what they do. They predict on the day that they were taken, within a certain range.
When Election Day came, one might have looked at the state polls in the 10 close states. Presuming that they were only one day old, everything depended on whose people showed up. Trump got out his people in WI, MI and PA. As I recall, the Clinton count in PA was about what they expected.
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MY BOTTOM LINE
The national polls correctly predicted the Clinton win in the popular vote, although they overestimated her margin by 1%.
The state polls were inaccurate in projecting the huge voter turnout in rural white areas, especially in the MidWest.
There are 3 problems with current polls, although they have their uses. First, the polls are national polls. Trump can certainly win with less than 50% of the popular vote. Secondl, it is early. Lots will happen in a year and half. Finally, the situation changes radically when the opposition party actually chooses a candidate. The negatives of such a candidate will be HUGELY more negative than today, after a long primary season and after a year of attacks by the Republicans. I would expect that Biden's positives would be much less then they are now.
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THE ECONOMY
If the economy is anywhere near where it is now, Trump will win easily. 4 years of growth after the Obama start would be truly amazing. If there is a recession, Trump will blame the Fed and everyone else.
No, they were not. Only two, I think it was, out of a dozen or more had the winner correct. And those two were often ridiculed in the weeks leading up to election day. As for the fact that the electoral college chooses rather than the popular vote, most of the polls you are referring to had Hillary much further ahead in the popular vote than it turned out to be.