Part of the problem with criticizing Trump is that normal people see the gold and the plane and the decaying Florida mansion and are hypnotized by the spectacle into thinking that the would-be emperor has clothes. There are a lot of detailed ways to frame how Donald Trump has no real qualifications to be President. But they are all complicated and require sophisticated arguments that take a long time and a lot of supporting detail, like:
a) we don't really know that he is successful because his companies are privately held, his FEC filing was as bogus as the "doctor’s” letter certifying his health and he won't release his tax returns. Problem is, he appears successful (especially if you have no taste). But everybody does know at least one example of a business that looked pretty successful until it didn't anymore: Enron. It's pretty easy to cook the books when you’re running a number of interrelated companies. We know he has enough money to live opulently because he inherited a ton from his Daddy. But without him opening his corporate books and making his personal returns public we have no idea whether what he's created is real, or whether it is Enron.
b) what Trump *is* successful at is branding. But a low-information voter does not know what branding is. Here is a way to explain it. Trump = Kardashian: both are very successful and have made a lot of money, but you don't want either anywhere near the nuclear launch codes.