Its <current year>, why do runes still cost so much

Rune Page = 6300ip Quints - 1545 to 6150ip Reds/Blues/Yellows - 1640 to 7380ip Page + Full Set - 12765 to 34590ip

So for a new rune page, and a complete set of runes, it costs between 2 and 5 new champions worth of IP, depending on which runes you need. Of course, these costs diminish over time, as you don't have to buy the same runes twice, but its still going to be 6300ip at a minimum, and a surprising amount of champions run non-standard runes nowadays.

The grind for runes is the most lengthy and unsatisfying grind in the game, lasting long after you've hit level 30, and making you feel punished for picking up new champions with atypical rune choices. The fact that Riot still hasn't made at least the runes themselves free is actually really disgusting, because the only reason they have not to is "because it would disrupt the IP economy", which is Riot slang for "It would make people acquire all the champions faster with just IP, and we'd rather it be slow so that players are encouraged to buy champions with RP".