Bernie was already that far left. Hilary has gone a little left to placate the outer wing as politicians have to do in primaries.
Re. Trump, maybe saying he went too far right isn't the right way to say it. Maybe a better way is to say he went too far crazy. Mexicans are rapists, don't let any Muslims in the country, etc. There are lots of people that stuff like that turns off regardless of their politics.
Suppose Trump did get elected. He is already hated around the world from this campaign. The US would have some major diplomacy to do just to get things back to how they are now.