You raise some good points about scalable online business models, but I feel that your approach may be limiting yourself. Obviously that's also apparent to you, or you wouldn't be inviting a discussion on the forum, but a business model really just defines the way that you provide value, gain customers and produce profit, which in turn informs the way it's managed. What part of it can't be scaled?
bitcoin mining, stealing the caps off fire hydrants to sell for scrap metal, developing a service that provides hamsters for data centers to power servers.