The more complete picture is that Drumpf's early business history was reasonably successful in creating buildings and getting them rented out. More or less, he learned at his father's knee how to build buildings, especially apartment buildings, and market the apartments well.
Update: except for the fact that he built buildings with illegal immigrant labor, ignoring basic safety regulations and bribing people to stay quiet about the matter. So his vaunted "business acumen" really has a lot to do with being a crook--someone for whom the health and very lives of his workers didn't mean bupkus.
He then, in the late 1980s, went into other businesses like pro football, casinos, and the like, and that resulted in his bankruptcies of 1991, 1992, 2004, and 2009. It's worth noting as well that these bankruptcies had a lot to do with businesses regulated and funded greatly by the government, so his record in dealing with government is suspect.
He also had disasters with ownership in the USFL, and has had major difficulties with a golf course in Scotland, famously losing a lawsuit to prevent a wind farm from being built.
In other words, Drumpf does very well at
Note: we are referring to the Combover as "Drumpf" because he, knowing full well that his family had changed their name from "Drumpf" to "Trump", made fun of John Stewart for changing his family name.