I addressed this topic below. Your income is only limited to $20 if you cash out today. If you hold that $20 of STEEM and continue working to improve the platform then you will magnify the value along with everyone else.
https://steemit.com/steem/@dantheman/building-long-term-value-from-your-blog
So cash out is a bad idea on steemit. You mean to maintain steem in wallet or SD or both?
Explain
What he means is that the in the future, the value of STEEM will go up, meaning that the 20 bucks you made today will be worth more in the future. If you think 20 dollars is too little, invest it by powering up, or keeping it as liquid STEEM, and cash out when the price of STEEM is high enough for it to be attractive to you.
Keeping it as STEEM Dollars means that the value will stay the same, though. SBD is always worth $1.
The liquid STEEM is that will go up or down, depending on the value of STEEM on the market.