Trump's father died in 1999, so it's not accurate to say Trump inherited his wealth, because he was already a billionaire when his father passed away, and his father's estate was divided between 4 children and several grandchildren. He did get a substantial loan from his father to get started, but he parlayed that money into a fortune. Many people have won substantially more money in lotteries than Trump received from his father and most of them blew through it in a few years. Clearly, there's more to the story than Trump being handed his wealth on a silver platter, he was dealt good cards, but he also played them well.
As for the economy, Trump is in a catch 22 situation. On one hand, like most financially educated people, he realizes that there are serious systemic problems with it. He even said as much repeatedly on the campaign trail. But now that he's President, if he was to be brutally frank about the situation, he'd cause a panic, and he doesn't want that because the mess will land in his lap. Instead, he's doing his best to turn things around while projecting optimism. Hopefully, the combination of renewed optimism and structural reform will allow the whole thing to keep going, but there are no guarantees.
There is always someone who enjoyed watching Obama blame his own failures on his predecessors and now will give credit to Obama for someone else's success. Trump is in the process of turning this country around and putting it back on the right track, and it terrifies the weak of mind. They were so close to the socialist state they wanted.