20k is enough to start earning stakes every 1 to 3 days depending on the network weight.
Yes the more someone has the better and more chance to stake often but I think 20k is good enough to earn a few thousand coins a month.
I have 150k RAIN. I receive staking rewards everyday 8-20 times, approximately 1000-2500 RAIN.
So, an investment worth at the moment less than 2BTC makes a passive income, which would be good enough to live comfortably for most of the people in the world (for some of them it's a fortune). Nice. I'm gonna do the same.