Well I dont think that it is possible to cheat a billion dollar company which has professional computer scientists if this company does not ignore this at least.
Having lots of money and skill doesn't fix everything. There are bots and hacks for basically every game regardless of how big they are; if the company figures out how to detect it with 100% accuracy the cheaters just create something new to circumvent it. This is why Riot does ban waves; it lets them gather all the cheaters they found and ban them at once so they don't have the chance to change their methods, and Riot won't tell them what they found because that info also helps them avoid detection.
As I said, Riot is actively trying to improve their system, but even when it's as good as it'll get you'll still have a game or so ruined by a bot before they are thrown out.
You never see the bots that do get banned, only the ones that haven't been yet.