So let me ask you; how much of the 580k would you have earnt if everyone did the same thing?

You're making that money currently because no one (or few people) actually are crafting/gathering, and when people actually do take the 'advice', the numbers aren't going to be anywhere near the same because everyone will be undercutting each other to get the gil.

I'm glad that you've taken the time to level your crafting/gathering skills, and are taking advantage of the market while others aren't/refuse to, but this solves the problem for you, not others.
Whether or not it is an effective way to make gil is not the point; players are paying their $15/month to be dictated on how they should spend their time (limited or otherwise) by such a design. It's fine that it is in, but Square also need to be aware that such players that refuse to take advantage of the market now, and want to play the way they intended to, and until now were given no indication saying they couldn't, will potentially leave and take their money with them.

The game has been out for two weeks, have given people plenty of headaches and in no way built any form of loyalty with new players. That isn't to say give everyone what they want, but when players finally get down to 10k gil on their level 50s, things will only get worse for Square unless they can explain why things should remain the way they are.