Yeah, honestly CDR is probably one of the biggest contributors to damage creep. Yet riot will never remove it, because much like their goal of reducing game duration.
They make decisions off of data, that they then make assumptions about, rather than community input and feedback. Which works, at least until your game is no longer growing, and changes only work to alienate subsets of your player base, without equally gaining new players.
This is the kind of philosophy that leads to statements like "you think you do, but you don't", all the while people are leaving the game because they are saying what they want but riot would rather look at the numbers and assume meaning. E.g. Malzahar revert.