His negotiating methods, if one can call them that, are like "single use weapons" that are relationship burning rather than building. If you are doing 100s of one-off deals with counterparties you will never talk to again, and who don't know each other.. it might actually work.

But you burn the ability to make more deals with the same counterparty again.

If you played this game with your neighbor over a fenceline or tree limb dangerously overhanging into your yard.. you would save a few bucks once, and have an antagonistic relationship for the next 10-20 years of living next to them. Good luck getting the benefit of the doubt next time.

Meanwhile mister Trump is doing quite well financially, so he is doing something right; and your theory is not covering the whole story.