Let us buy Champions in Champ select!

I've been playing for a little under 3 years now, and I have a little more than half the roster of champions. I'm sitting on like 20,000 ip right now and no matter what i'm saving the 6300lp the new champion (Aurelion Sol HYPE), but while obviously 20,000 lp isnt enough to buy half the roster, if it enough to buy a least a few other champions.

With the new champ select, its easier now then ever to set up trades with your team. But sometimes, they change their mind after they already picked my champ, but I don't have theres. If we have the ip, we should be able to buy champions in champ select, just like with skins, dontcha think?