Michio Kaku is first a futurist and second an entertainer and third a physicist. He hasn’t published any research since the 90s from what I can tell, and all of his work back in the day was around string theory, which is more or less discarded today because it’s not falsifiable. Clearly he needed a lot of mathematical skill to competently study and discover new string theory concepts, but since the 90s he’s mostly been a science entertainer and a crank babbling about quantum computers, longevity, superintelligence, parallel dimensions, and extraterrestrials, all of which are distinctly not his domain of expertise and most of which are unfalsifiable.

Michio Kaku’s job is to go on TV and go on podcasts and talk about science fiction as if it were real to credulous hosts.