Trading is not something that requires us to be on our laptops or mobile phones for so many hours, some professional traders do trade whenever they want to relax, so you don’t have to quit your job just because of trading. You can just go to work in the morning, whenever you are back at home, you can just decide to trade and relax yourself.
There are some who are spending hours finding the perfect entry and if you're working for 8 hours, this will just be a distraction especially if they're making way more money in trading than working for 8 hours. I'm talking about those swing traders who are expert enough to make money in trading. Maybe if you're a position trader then you can do both of them, but there are some who just prefers trading maybe because they don't want to get stressed out that much.
Also, having just a source of income doesn’t make sense to me, we are supposed to have multiple sources of income. In case anything happens to one, then you can depend on the other, so if you depend on only trading, if things end up getting difficult and you're not making much money from trading, then how are you going to be surviving? So I believe trading should be an alternative source of income since you don’t have to spend all your time trading.
We have this mindset of having multiple income source is better, but there are times where one income source should be enough for a person to pay his bills, invest into something and live the life that they want. Expert traders are like businessmen for me. They're expert only in one thing, but they can make money from it because they know what they're doing. Having multiple income sources is better, but not a requirement nor a need.
As for trading being an alternative income source, most of us prefer that way, but there are a few experts that doing it as a full-time job... because why not? I mean if you're earning 3-4 digits per day in trading, why should you go to work, right?
Most people who decide to quit their job just because of trading might end up regretting why they did that when they are no longer making much money, because I saw people complain about how they lost most of their money in trading during the last bear market, actually most of them were participating in future trading, which we all know is very risky. So just imagine you left your job to participate in trading, and you lost everything, you won’t have a choice but to start looking for a new job.
That's the risk. A risk that most of those who quitted on their job didn't saw. They thought that trading would be a better source of income than working 8 hours hence, they quit on their current job. Trading is a very risky "JOB", so quitting your current work for the sake of trading isn't advisable. I said this in the past, but maybe if you're consistently profitable on a monthly basis for the last 2 years then that might be a sign for you to quit your 8-hour job for trading.