He often presents populist ideas, even when they aren’t in line with his normal rhetoric.
I think he does it to grab attention or appeal to people with that idea. He then spews a ton of well-polished half-truths and straight lies to make whatever point he was after in the first place.
It’s not uncommon for anyone to agree with a sentence or two from him out of context, but in context, it’s all garbage.
My understanding of a patent (in the US) is that it’s only for new, novel concepts, often difficult to design or conceive.
Prior art, in this context, are just examples of this concept already in use or demonstrated. If there are already examples of the idea in use by others, then your idea isn’t new (and therefore not patentable).