The value of his ventures depends on him as a brand, and there are lots of people invested in his ventures, so it benefits a wide range of interested groups and individuals to carry water for him. It's a mixture of his own PR, PR from related ventures and investors, grifters who want to appeal to his audience of rubes, and the rubes, themselves. There's probably a limited amount of coordination at the formal PR level, but I'd assume a lot of it is emergent behavior.