In general, if an idea/niche is profitable, you will have competition. In fact, if you have idea and there seems to be no competition, that should itself be a red flag.

Fortunately, virtually no markets are truly "winner take all." And having a lower threshold for how much revenue is "enough" makes it such that you can justify attacking niches that are simply too small for a company with a huge valuation that needs to show growth multiples.