So, there are certainly valid questions about whether one can build a "Netflix-of-$NICHE", but I want to point to a lovely little example named Crunchyroll.
You can definitely succeed in a niche, provided you have some factors in your favor:
1. An audience that is dedicated to the content you serve
2. The ability to focus on the niche provides you a greater library than broader competitors have
3. The ability to market yourself in such a way that you build reputation with the core audience
The end result is you can create a product that other people will pass up competing offerings for that might have broader appeal - or will simply subscribe to both.
Netflix used to be the go-to for Anime for a long period of time. However, Crunchyroll was able to provide a much more massive library of anime on-demand and catered to the dedicated fanbase.
I tried to watch an anime on there once. When I clicked play I got a preroll ad, fine. 30 seconds in, the same ad played again. I hope that's not normal because if it is I have no idea how people can stand it.
You can definitely succeed in a niche, provided you have some factors in your favor:
1. An audience that is dedicated to the content you serve
2. The ability to focus on the niche provides you a greater library than broader competitors have
3. The ability to market yourself in such a way that you build reputation with the core audience
The end result is you can create a product that other people will pass up competing offerings for that might have broader appeal - or will simply subscribe to both.
Netflix used to be the go-to for Anime for a long period of time. However, Crunchyroll was able to provide a much more massive library of anime on-demand and catered to the dedicated fanbase.