Well, have in mind that some people accumulated a lot of coins in the early days and now they can trade with huge capital! I guess for those people it's more profitable to spend time analyzing the market and making trades than sitting in some office for a regular salary every month!
It's hard for small players, with small bankrolls we often choose higher-risk trades in order to make some meaningful profit, but because of that we often face losses... so without some nice capital it's impossible to fully depend on crypto trading as the only source of income!
that not all could able to attain or achieved thats why it would really be situational but pretty sure that this is something that cant really be achieved easily but its not impossible.
Be sure that you do make yourself able to sustain your living before you do quit up your dayjob or else you would really be putting yourself on big trouble.
You are right with this statement, only you who can find out if you are capable of doing such thing, it's your hard work that will allow you to find the best and suitable way to harvest good amount of profits each time you deal with your trades, it's not impossible but it's also not easy in terms of succeeding on this kind of business. With the heavy fluctuation and unpredictable market run, it's your good decision making that will lead you to make a decent amount of money.
Never to take a quick action like quitting your day job if you are only making good trades for some time, make sure that you already established and you already have good system and strategy to make money out from this field.