Speaking of direct-response techniques, nice headline! I see what you did there.
As a career and current practitioner of the DRTV arts, I see your point. But … I think you are confusing persuasion, in general, with infomercial-style persuasion. Trump is a Master Persuader (HT: Scott Adams), so his techniques will have commonality with any craft that uses persuasion as its primary tool. Negotiators will see a negotiator, etc.