Even if it’s not a scam, it’s probably not material to anything in the commercial world for a couple of decades
I'm not so sure.
IF, and it's a big IF, they do have a room temperature superconductor, then this will be a major, huge, massively disruptive new tech. If they truly have it then I feel things will change FAST to adopt and push this new tech.
Again, it's a big IF, but expecting it to take decades to play out in the stock market would be overly pessimistic IMHO. Would be interesting to see how such a tech would impact Tesla.