My cynical assumption is that most startups start out with a grand vision that they overpromise and underdeliver on. Especially if it's a content creator, where I assume that they started with a need to monetize their brand and then came up with a product idea.

This guy claims to be different in that he has enough money already and he's just trying to make the world a better place, but pretty much every startup makes claims about how they're different and therefore they're going to succeed. They can't all be right. I'd prefer to hear unbiased opinions about viability from intelligent people on HN/reddit/twitter rather than biased opinions from the guy who's trying to market his company.

I'm not saying that this wheelchair is going to flop, I'm just defaulting to skepticism of new ideas in general.