This may well be a wild theory. Much of the public is disgusted by candidates almost wholly beholden to their wealthy donors and super-PAC's. Only those able to write "two-comma" checks (>$1,000,000) appear to have any voice in the process. Citizens United v. FEC has fueled much of this behavior.
Trump appears to answer only to his own wildly narcissistic self. He is able to easily self-fund, and able to thumb his nose at the Kochs and their ilk. This recent WSJ article sheds some light on this issue: http://www.wsj.com/.... Trump appears to be tapping the angry base. Does that base really care whether Trump is not answering to a super-PAC? Does that base really understand or care about the impact of Citizens United? Does the base care whether Trump is perhaps the most moderate of the Republican candidates? I really have nothing more to say about the Donald that has not already been discussed on Daily Kos.