Dumb, but he was like, there.
Just look at that press conference with Musk. Trump looks defeated and tired. Musk's crotchspawn mumbles something to Trump that was probably insulting, and he's just, like, whatever. Musk was completely in charge. Hitler didn't do big appearances where he let some big business leader do all the talking while looking like he wants to take a nap.
If there were a practical fusion reactor shown today, it'd be 10 years before it could be started to be deployed at commercial scale.
More to the point, fascism isn't going away just because we have better electricity sources. Cheap power is a problem in capitalism.