Why can't new players buy tier 3 runes?
I understand that the reason players under level 20 are prohibited to buy tier 3 runes probably because it stops smurfing players from getting runes and making the experience worse for newer players. However, I'm leveling up this account right now and I'm finding it really frustrating that I have no runes. I almost always lose lane to opponents who have runes. (I still queue up with my ranked friends on their main accounts.) Why can't this be changed?
TL;DR Why can't lower leveled players buy tier 3 runes?