A Simple Way to Think about Business
Business is simple. People pay you because it is easier for them to pay someone to do something rather than doing it themselves. The more difficult it is for them to do, the more they are willing to pay. If you have something to sell, and if it's something that is not readily available, then you'd have an opportunity to sell. And if you can do it consistently, you can run a business. This is because you did the difficult part that others don't want to do or are incapable of doing.
The difficult part of business is to predict what people want; they call it "demand." Every business requires time, effort, and preparation until it can start. Therefore, predicting the demand is a challenge. You can predict any kind of demand, but the reality comes only after you start taking actions based on your hypothesis.
Once your prediction of demand proves itself true, meaning, people start buying your things, you'd have to put your effort and resources to expand your unique appeal. By doing so, your business would become stronger. Strengthening the business contributes to its sustainability, however, the danger lies in the changes in demand.
Without being able to change the business accordingly, your business would become extinct. The strength of the business doesn't depend on how big your business is, but how adaptable it is to changes. The concept is similar to that of dinosaurs and rodents, in which dinosaurs couldn't adopt to the environmental changes, but rodents could.