Why? No offence, but your reasoning is dogshit. You pull an arbitrary number out of your arse and say there should be no more than that because you couldn't keep track of any more? What about people who could keep track of 10,000? What of those that can only keep track of 10? Fuck those people because they're not you, right? Sorry, but that's just bullshit.
While I will agree with the basic idea of quality > quantity, they're both purely subjective and you have no right to determine how much quantity is too much, or even that there's a single quality Pokemon among the existing ones that would preclude the need for more in the first place.