[Shivetya]

why not have stairs between the escalators with arrows painted on them indicating up/down if not two sets clearly divided by the escalators themselves?

One thing to take into mind, you have to set your rules based on the lowest common denominator or the most disruptive. When people don't have any expectation of being punished for not respecting others or the rules they are in the most disruptive category. Hence they will stand on the left regardless and as such you need to adjust for it. Face it, there are just too many rude or don't care people in this world from a generation or two of being told its not your fault or others will adjust to you.