First of all, niche refers to the long-term demand of consumers, and the demand is not too great.
However, the explosive sales cycle of the popular explosive products is not long. I've used EDX to observe small categories several times before.
Some time ago, the black technology ear picker, as well as the potted plants sold yesterday and the day before yesterday, are all small categories. The former lasted for two or three weeks, while the latter disappeared today. It is also considerable to sell more than 10 thousand a day, but it is not easy to operate by short stories for a long time.
Data source: EDX data eye
It is ok to pursue short-term profits and run small classes.