If you're a well known and successful trader, there are many ways to make a side earning other than trading. For example, you can try to open class for teaching other newbie traders and share tips about trading as well. Remember, knowledge is a valuable tool for you and others too.
Yeah, if you are hard working enough there are plenty of stuff that you can make money from crypto, from signature campaigns to bounties to airdrops to many other stuff, there is also plenty of regular jobs as well, community manager, brand manager, campaign manager, content writer, designer, coder and plenty more that could make money on crypto world.
Long story short if you really want to have a pure crypto income, and if you start early and keep working for months, even years, eventually you do reach to a point where all of your income is pure bitcoin. I know it because I have done it myself, haven't worked for fiat in over 4 years, been purely crypto. Of course when I need to spend it, I cash out to fiat because there is not really all that much I can pay with crypto just yet (hopefully one day).