I hardly take any of the "Game Theorys" seriously, (Though i admittly like the Bowser one) their all bullcrap pretty much (Like seriously how the hell is Mario faster then Freaking Sonic the Hedgehog?)
pretty much what @TB100 said, i mean seriously, Sans is Ness? Plus the "proof" of most of his theories definitely cherry pick his info and never sites stuff. Though i will say every now and then he makes a good theory. i'm just there for Ronnie and Gaijin.
All of Game Theory's videos are parodies, they're ment to be comedy, never to be taken seriously. If you follow the logic, Rosalina is kinda pointed out to be Mario and Peach's daughter, for example, but Game Theory made it fun to place Luigi as a twist. Of course it's not trying to prove anything, just making us laugh.
I personally like their ideas and had fun watching them, however, I unsubscribed when they started having pay to watch contents, I hate when that happens, I just quit.