That's because they're not being held accountable for a wide enough variety of infractions. With enforcement primarily focused on speed, how do you get it through drivers heads that they are to keep right except to pass, not tailgate, etc...

Driving etiquette is pretty much dead. I don't think change in enforcement method will have great impact on anything. Gradually improvement of driving education and testing practice is key. Obviously won't happen because Gregor wants us to ride bicycles. So pretty sure we are hopeless. :)