The methods by which Trump has increased his personal wealth over the years likely did involve "success" but that word likely covers a variety of actions including tax evasion, not paying his debts and engaging in shady business practices not to mention benefitting from tax laws written to keep the rich rich. 
Most Americans come from a variety of ethnic backgrounds, including white people. More than likely you too are a "mutt" and there's nothing wrong with that. Donald Trump, on the other hand, has frequently brought up his belief in eugenics, a racist doctrine espoused by the Nazis. 
It is idiotic beliefs like this, not to mention the general perception that Trump not a credible candidate that will ultimately cause him to lose the election. Some white working class cretins will vote for him but not enough to get him and his former escort wife into the White House. 
It will be extremely amusing to watch his concession speech.