It's hard to say about his motivation but one theory is that he's always been a grifter, he considered everything he took as his own personal property and potential assets for later sales for massive amounts of cash (or trade for favors, payback for favors). Only suckers and losers don't take full advantage of such opportunities. The well being of the USA was never his thing; as an extreme narcissist the well being and WEALTH being of him and his family brand is everything. Being president didn't change his character. A recent example is how he buried his recently departed ex-wife in a place to create a massive tax loophole.