Is this Riot's real intent for creating strong champs?

I've always wondered if Riot nerfs champions after they become popular simply to force the competitive players to choose the next best champion in order for players to potentially spend rp buying the new meta champion. From a business model this is great as they keep 1/4 of their champion pool in the meta then nerf them so that the quarter changes to a new set of champions. Just rinse and repeat the cycle while feeding new champions into it every few months and your on your way to making money.