It's unlikely no one buys your product
More often than not, the bar is set lower than you think. Meaning, in a world with 8 billion people now, it's more unlikely that no one will buy your product than it is unlikely that someone will. Basically, someone out there will find value in your product.
Don't believe that's true? Remember that 8 people bought the I Am Rich app that did absolutely nothing but cost customers 5,600 after fees from the ridiculous application for doing pretty much absolutely nothing.
And that makes me absolutely certain that if you provide your customers with a single iota of value that you can generate revenue. That doesn't necessarily mean that your business will be around for the long term—for Apple did remove the I Am Rich app without explanation in 2008. But, it sure does give grace to builder like me that there are real, paying customers out there hungry for my product.