The Blue/Red Ocean concept isn't about the size of the market, it's about the lack of competition in the market either by being first in a clearly new market, or by differentiating your offering from others to the extent that you're not competing for the same consumers. There's a book "Blue Ocean Strategy." It's worth a read for the explanation, and the case studies. There's worksheets and process too, but that didn't lend itself well to listening in the car.