IP Skin Champion Skins
Riot does RP skin sales. How about adding a 10x IP price for those skins just on sale. This would allow veteran players to eventually (and depending on multiplier) and very quickly burn up their IP.
Example from this sale Star Guardian Lux original 1350rp sale 675rp. Maybe allow IP purchase at 13500 (or maybe 6750). The multiplier can be set up by Riot.
Maybe I don't understand the business model goal for RP skin sales. But it seems like a good way to allow IP to have a purpose. But it is only luxury and very expensive. 13000 x 10 = 100,000 IP so people will burn through it soon. For new players they can have a goal to collect IP, although it would take a long time. And since it is time limited, you still have to choose between waiting for the rotation or just buying it full rp.
Just an idea. Maybe they don't like taking away $$ just to reduce IP.