the limit for income exist, you don't have infinite fans. And a 30k arena don't means 3 times higher income then a 10k arena, maybe we have in future team who could earn 700k a week, and even for that 200k for a single player is pretty much.
The limit for salaries also exists -- you don't have to train a player until he has a gigantic salary. Or, indeed, buy a player whose salary you cannot afford.
"I don't know half of you half as well as I should like; and I like less than half of you half as well as you deserve."