Consider the size of the opportunity

Small and large companies can encounter similar early difficulties. Both need customers, reliable work, and enough money to continue. A modest ambition does not remove all risk.

Consider the possible value if you succeed. How many people could benefit? How important is the problem to them? Can the market become larger as the solution improves?

The present market is not always the full opportunity. A useful solution can make an activity possible for people who previously avoided it. The company can serve existing demand and help create new demand.

This does not justify an inflated market estimate. The distant opportunity gives direction. The immediate market gives you a place to work. Keep these two functions separate.