The thing with app development is that it takes a lot of time but if the work gets divided between people it takes less obviously. Now there are people who develop app alongside their actual daily job and there are those whose job is to develop apps as their career.
Now you can as well develop apps if you understand the basic of android, kotlin and other stuffs related to it. You have to keep app resources (images, icons, fonts, gradient and other assets for app building) closer when working on app of your desire. Also one more thing, you have to keep up with newer tools and tech that are getting updated with android with pretty much every year.
Now if you are impatient and doesn’t want to go through the hassle of building the app yourself then there are plenty of people ready to accept a contract from you to do just that.
Now as for community based mobile application it depends on what kind of app you would want to build. Is it a streaming app or any kind of keeping track of certain stuff like new releases of upcoming episodes, etc.? Whatever it maybe if it costs time and resources then it will cost you money.
For me, I like the environment where certain group of like minded people who do their daily jobs and develop a particular app in their free time. This kind of culture is uncommon these days. Then there are people from all over the world contributing what they can hence saving a tons of time for everyone. In these kind of situation, fundraising as well donation are setup so as to support the core developers. Money comes from two kinds of people. First, the people who likes to support the developers for their hard work and secondly, there are those who want to see the app in development to grow and see how far can it go.
So I hope this answers somewhat to your query.