Why do additional rune pages cost 6300 IP?

As if runes by them self don't cost too much, why does an additional rune page cost so much?

I know that runes can completely change a game, so they should be hard to get, but why do they cost THIS MUCH? Especially a new rune page, that could be very helpful for you, but 6300 IP? Are you kidding me?

I honestly think that runes NEED to be changed because this is just insane. Some Quints already cost 2000 IP, seriously, it can take sooo much IP just to fill one page. And with champions that we also might want to buy, this just makes it all too hard.