The history of tech is littered with the corpses of those who dreamed big with their head in the clouds, dabbling in things that seem like they could be great but in reality have various practical down-to-earth low-level problems that need to be addressed.
It takes a substantial level of compromise and discipline to reign in scope and ambition and do the hard, un-sexy work needed to make something REAL. Something that functions in the real world and does its job the way people expect it to.
At some point the rubber has to meet the road. Someone's got to roll up their sleeves and make it happen. If you watch any of this guy's videos and pay attention to his thought processes, you can tell it's not his way. He's an idea guy, a dreamer, not a practical get-it-done guy.
He should've recognized this weakness and teamed up with the right person (or people) to complement his skills. But for whatever reasons, he persisted on going it alone. Hopefully others will learn from this.