It could be that there is no market per se, but it can be more subtle than that.
There could be an easily identifiable market that is big enough to provide you with acceptable revenues... But it could be that this market is too difficult to satisfy! There could be any number problems:
- The solution they need is terribly complicated but their budget is pathetic and will never allow you to recoup your development costs.
- Or the problem they have is very convoluted but they expect your solution to be incredibly easy to use. Some markets are full of people who say things "this is too complicated/unfamiliar, I'll just do it on paper/FAX it to them/put it in Excel" or any other shockingly antiquated thinking.
- Or maybe the market looks to be uniform from the outside but once you dive in you realize that each customer in the market requires your solution to work in a different way, making it very hard to please even a subset of the market.
- It could be that the entire market needs your solution to interface with product-X, but that vendor won't even talk to you for any number of reasons (exclusive with someone else, they think you're a joke, or whatever).
And on and on...