Yes, you can make a course for a low demand topic and still see success, but it usually only happens in two scenarios.
Scenario 1 is that you’re making a topic on as brand new thing that’s rapidly growing in popularity, so it’s only a matter of time before people start searching online for courses on the subject. This is pretty typical with new softwares, for example. The market just looks weak because well… your topic isn’t well known yet but it will soon be.
Scenario 2 is where there is demand for this information, but no one has taken the plunge and tried to make a good course on it yet. If there are no courses on the topic to sell, then Udemy isn’t going to have ant data to say that people are indeed interested in it.
When I made my first course called “Mastering AirBNB”, there was only 1 other course on the topic, and it was very poorly made. When I made my course, Udemy noticed that it was in fact a topic people were willing to buy, and eventually started promoting it. When you think about this second scenario though, it’s usually obvious in hindsight. Airbnb hosting is a side business and it makes money for its hosts. Businesses and money making skills are always popular online courses on Udemy, so it had a leg up there. Not to mention, Airbnb was on its way to becoming a global phenomenon and household name – you didn’t need a crystal ball to see that happening.