Never encountered this dude before, but as a huuuuuge Paper Mario: TTYD stan, it piqued my interest. I think his theory makes a whole lot of sense, and also explains things like why we haven't seen a new metroid in ages (it also makes me wonder if they postponed prime 4 and brought back the old developer because they realized they couldn't make a metroid by removing the metroidvania).
Same, I love the bit from his Mario Maker list videos where he treats his rating numbers as physical objects he had a limited supply of lol