Then you thought wrong. The vast majority of the time notarized signatures are unnecessary. Adding that as a base requirement of all legal contracts is a terrible idea. Did you get a notarized signature last time you bought or sold your car (either with a dealership or privately). Because if not then you already failed to meet that standard.
I agree that letting things get so casual as to start "signing" by text is a bad thing. Handshake agreements are things you do with your neighbors, not with large businesses. But requiring a notary for every contract is going too far in the other direction.
By the sounds of it all they brought to it was the name and maybe some technical knowhow. Because everything else about their business seems to have been abandoned. The only way to get further off from "we'll make electric conversions with preexisting parts" is to abandon electric cars as a whole.
He may not deserve all of the credit, but it sounds like he deserves something north of 90% of it.