Actually, at this point, a cardboard cutout of Elvis would be leading Trump.
Good thing the election is not today, eh?
Aside from the immediate aftermath of 9/11, George W. Bush was close to 50% on only two days in his entire life. Election Day 2000 and Election Day 2004.
Presidential Preference three years before the election is irrelevant.
This is why the founders specified election DAY, not election week end not election week not election month DAY
After the Gulf War in March 1991, George H. W. Bush had an approval rating of 91%, yet he managed to blow it and lost 20 months later to BJ Bill Clinton.
As you said, polls three years before an election are irrelevant. A lot will happen between then and now, both good and bad.