I think people not being able to vote because their right to vote has been taken from them, or their vote was made pointless through gerrymandering, or because of other acts of voter suppression does change elections. The ability for it to change the outcome of a race is why voter suppression happens.

People who don't bother to vote for any reason changes elections. It also makes it very hard to make claims about what the majority of Americans want, since so many didn't make their opinions known

You can't gerrymander a presidential election. How would that work? It's not district-based.

A majority of Americans either wanted Trump or didn't care enough to vote against him.