> it could be argued that he only didn't win the popular vote because he didn't focus on that,
This is exceedingly unlikely. At least not without major platform changes. A trump that appeals to an additional 3-5 million people looks significantly different.
> I think the founding fathers would cite our current president as the reason they didn't trust direct democracy
This makes even less sense, a more direct democracy (proportional approtianmemt in the house and senate) would be a much stronger check on an unpopular president. What you're seeing now is what happens when the value of votes are distributed unevenly, such that a party can appeal to a minority while retaining political power.
That said even if it were the case, a popular vote would have other useful far reaching consequences in terms of how federal funding is apportioned.