@GravityTaxes I'd assume after 10 years of operation, the mechanical parts of the escalator would be worn out in an extremely uneven manner if people always stand on one side. In other words, the escalator will last for a shorter time before needing a overhaul compared to the same amount of people standing evenly on the right and left (or middle). I'm no elevator/escalator engineer/technician, so I wouldn't really know, but it's also possible such an uneven wear might also lead to malfunctions that wouldn't otherwise appear, as gradually one end of the various critical components would be out of specs whereas the other end wouldn't. That's worse than both ends getting thinner/shorter/smaller/etc at the same time.
But yeah, this is just a guess.