Trump actually does very little developing in New York these days. And not all that much elsewhere - for quite some time, his business has been more of a licensing business than a real estate development business.
He got things done for the shareholders of his companies and as president will get things done for Americans.
Trump's companies are privately held. His "shareholders" are Trump.
Then he did what he did to make his company successful. And he does have partners and/or subcontractors who succeeded because of trump’s success.