Trump banned bump stocks because he thought they were too close to machine guns.
Ron Paul and maybe Massie are about the only politicians of my lifetime that held any real power that I can think of that would even entertain deregulating machine guns.
Incidentally, the longer forced reset triggers stay legal, the more real machines will have their value growth slow and, almost certainly, eventually tumble. The only reason this hasn't happened yet is because most people aren't yet familiar with them and many of the people who are just kind of assume that once they really go mainstream the government will put a stop to it, meaning "real" machine guns maintain their special status and therefore their special price. If FRTs stay legal for a long time and survive public scrutiny, then confidence in their future will grow and they will then eat much of the market demand for machine guns.
Of course, some machine guns would always remain valuable for their desirability as antiques, as long as people remain interested in them. That presumption of future demand for your collection might be a relatively safe bet for cool old guns in America, but it's still a bet.
They could likely get away with banning the FRT and bump stock through amending the definition of the machine gun in congress, just not the executive branch.
The ruling on those had nothing to do with overruling any part of the NFA. Only correctly identifying that FRT and bump stocks do not shoot automatically more than one shot by a single function of the trigger, which is what congress said would be the things allowed to be called machine guns.
Ron Paul and maybe Massie are about the only politicians of my lifetime that held any real power that I can think of that would even entertain deregulating machine guns.