Why not attach 3 rune/mastery pages to every champion u own?

Why not attach 3 rune/mastery pages to every champion u own? So it's even easier to customize your "loadout" before a game during champ select. I have difficulty scrolling thru my 20 rune/mastery pages to find one suitable for the particular champ (out of about 12-15champions I play) and then face limited time to change/further customize my option of masteries. When u pick a champ, 3 rune/mastery pages attached to it are immediately available for view - That seemed to me to be the best, most logical way of selecting "runes/masteries loadout" for champions.

Because facing the future, the process of picking rune/masteries will only get more complicated the more champs are added into the game = the more diverse champs u play.

Is there technical difficulty in doing that? It just seemed to me to be the most logical way of doing things. Make us pay IP to 'purchase' that convenience or whatever... I really need that.

It hurts my mind when I want to play a champ I don't usually play and then try in that limited time to figure out what runes/masteries to pick for him. I need to customize that info beforehand... and be able to process that info at once during champ select... so I have time to think about the strategic stuff like team comps and champions compatibility/counters etc.