Assuming we don't go back in time and change history to produce President Hillary Clinton (2009-2017), either Biden or Sanders would have won. Biden would have prevented the hemorrhaging of previously-reliable WWC voters in pivotal states and Sanders would have completely negated Trump's appeal as an "outsider" to leaning voters across a wide variety of demographics. Either way, it would have been enough to keep PA/WI/MI in the Democratic column.
Sanders would have lost NV though , and maybe even VA
Well, not to mention the guy went through the primaries pretty much completely unscathed because Hillary didn't need to go negative to win. I feel like "outsider" could become "ostracized and ineffectual kook" pretty quickly.