Why is Riot Games still using an outdated client?

Why is Riot Games still using Adobe AIR 2008 as their client? Many new processors, more specifically anything newer than the GTX 970 are better optimized with a newer client. I know this doesn't seem like a huge deal, and that some people can deal with it, but the number of errors is ridiculous. I'm not just bringing this up because of my own issues, occurring a different type of out-of-game client crash that happens once every week or 2. In my group of friends, we all have client issues, and all of us have different PC's in some shape or form. I wanted to voice my concerns to the support staff rather than going to social media, and any feedback related to the direction Riot is going in solving these problems would be great.

Thank you for your time, Moist (Alex) Justice.