Building apps is not relatively easy. To be honest, although there is a lot of money in the app space, most developers do not make money from having their apps on the App Stores(Most developers do not even have apps published). So the question is why do people do something that is difficult and they do not get a big reward.
Process over reward
Well, the simple answer to why we make apps is because we love making apps. You oftentimes question if you are good enough, you have the feeling of quitting and doing something else. But you find yourself the next day doing the same thing.
For me, I find that is the beauty of the whole. With time you learn your reward is the process itself, more than anything else. Next time you feel frustrated remember to enjoy the journey because it probably is 99% of the whole thing. The reward is just a small part of it. Don't judge yourself by the reward alone.
You never know when luck strikes
Every time, you hear stories of that developer who published an app and got thousands of downloads, and they didn’t even plan for it and end up getting revenue that they never dreamt of. Well, maybe that could be you.
Develop more apps and keep publishing them. You will learn a lot from that and it increases your chances to be lucky and get out of the rat race.
Some braggadocio
Don't you just love that feeling when someone asks what do you do? and you say I build apps. The expression on their face is priceless before they ask isn’t it difficult.
People use apps and believe it is impossible to build apps and you actually show them it’s possible. Sometimes you get to mentor a few and teach them how to make apps, Which I think is more precious.
There’s nothing else you rather be doing
For most app developers there is nothing else they would rather do than build apps. It is tied to our ego and self-worth. It is part of who we are. Something that gives us a sense of purpose and belonging.
So don't be frustrated you didn’t get that job, that you lost that client, your startup/app failed. Remember there is nothing you’d rather be doing than building apps, restart the process because it's what gives you purpose in life.