You know what this sounds like to me? "If you don't get lucky it's your fault for not doing it right/working hard enough" This is a bad point you're making. It's the kind of mentality that MLMs use. It's the type of mentality that the US uses and keeps people looking down at the poor and blaming them for their failure. You can do everything right and still fail. And that's not a small chance in a world like webcomics. You can push ways to increase their odds. But using those discussions as an excuse to not acknowledge that plenty of people will never achieve it no matter what is not a good way to approach the situation.
Do your best. Here are some tips on how to maximize your odds. Nothing is at all guaranteed and you can do all of this and never make it. But if you enjoy doing it you should keep going.
That's how you do it. Work on your delivery