Bingo. If there's nobody else already out there selling what you're thinking about doing, there's probably a reason. And the reason is probably not "nobody thought of this yet".
And odds are, if there is just one player in the market they're not very good. Simply by virtue of being the only one; the odds of that being the case simply because they are amazing and perfect is so miniscule. It's most likely that no one has bothered, or had the effort to out-do them.
An established competitor guarantees there's a market. You'll just have to do it better than they do.