First of all, you can’t solve a problem you’re not willing to work on.
Second, no one is expecting a solution that bans 100% of cheaters and has zero false positives. We all know that’s unrealistic. So saying no one has solved it yet is kind of misleading. There are existing solutions that work well enough for most people.
Third, there are solutions that can run entirely on the server side that would work for every system. Riot just isn’t willing to use them.
My comment stands. Bad engineers that can’t solve a problem other people have already come up with solutions for.