An Individual freelancer can work in niche technology, CMS or framework where the expertise of the individual in a niche can help get freelance work fairly easily on freelancing sites.
Can the same be said for companies who hire other people to get the job done?
Companies recruit people to get the job done and the obvious choice of a niche for companies are broad in nature like Web Development or Web Design or WordPress Developer but as an individual, you can always choose a micro niche.
Niche is the biggest asset of individual freelancer on a freelancing site like Upwork as it helps them grow and become experts in niches. (An article I wrote about how to find your freelancing niche).
An example can be Discourse Development. As of 30th October 2016, there are only 10 open jobs on Upwork for Discourse (BTW discourse is a new community software in Ruby on Rails). Compare that to WordPress which has 9726. Now search for discourse developers and there aren’t any.
So the question is can a company be formed when working in niche technologies where the amount of work is low and can they find enough talent to get this work completed?
I believe so. The choice of niches can be small but it still needs to have a growing interest over time.
Once the company has the right niche, it can always hire people to be working on such niche technology which may be built on a programming language where they have ample developers for hire. You may not find Discourse developers, but you can always hire Ruby on Rails developers and train them to work on Discourse.
Apart from that, a company can partner with a team who works in those niche technology to form an alliance and make a win-win situation for everyone. Niche can make you rich.