Much like an irrelevent governor of Arkansas or Georgia could not defeat a sitting president. Nomination = Possibility. The average American will have to "pick one"; if it's Hillary versus Hunter, I don't see that she has an overwhelming advantage. She is patently dishonest, has a history of graft (cattle futures), is as divisive as possible and I think Hunter would start with about 45% of the vote locked.
Then it is obvious that you know very little about American politics.
America has traditionally prefered Governors as President and has picked 4 for the Presidency in the last 30 years and all but one went for 2 terms.