That's your problem.. You're making money the same way you did when you had no money.. You're not reinvesting to make more money.
I think throughout all my gameplay so far, I've always been able to spend 10-15% of what I have each day.. when I had less money, I would sometimes invest 95% of them and just walk around with 20k gil..
I'm sure for OP that'd be rather difficult to spend 200million gil each day as an investment.. But it's certainly possible to spend upwards of 5, 10, even 15 million gil. You spend it, and you make it back and then some.
That way, your bankroll grows exponentially, where as, using your methods, it'll always be linear. You make 200k a day, 200k next day. Even if you have 200m in your hands, you'll still be only making 200k a day. Nothing wrong with that, but if you're not willing to spend any money, you're bound by time and you only have so much of that.
If you've been around since launch, and the OP also.. you may actually have similar number of hours logged on the game

Making gil's not about brute force labor, it's all about efficiency. Especially true in this game, it's the little things that make money, not the mindless grind.
Also, notice the Ullikummi lucis on OP's screenshot

That's a moneymaking saw.