Let's say you make an incredible mousetrap, better than any before. Then you tell some people about it, they buy it, and stop thinking about it because it isn't central to their existence.

You've now saturated your market and have no ability to expand easily without putting effort into marketing or advertising. How do you go from there to 10 million units sold without a marketing budget of any kind?

What about if the package is extremely off-putting to people outside your culture or if the language on it is confusing. How do you know without measuring?