It’s hard to leave your current job when you have a family to feed, I’m really guilty on this thought. But unless you won’t start taking risk, you won’t land into another, your dream job that pays over the other job. However, this is quite easy to say but actually hard to do when you’re in the real situation. It’s easier to just add another income than to completely quit from your job.
And it's also harder when you've been used to it and have been part of your system and daily life.
You're right, that it's easy to say that someone could do other things other than their jobs when it's paying them. They say that 9 to 5 is going to be for their job.
While the next hours is for their dreams. It can be done but not everyone still have got the energy to do it. But as long as there's a will, there's a way as they say.
If I am in a job that pays well and it's easier already because I am used to it, I won't leave it and just like what you've said, I'll look for a side hustle.