How does paying for a travelcard or bus pass discourage people from
tavelling for just one stop?

My argument is that most people would not pay for a bus pass or travelcard
in order to make a journey of at most few hundred yards in a very crowded
bus in discomfort and also one that on average would take longer than
walking, and even less would pay a single fare to do it. I personally
wouldn't do it with free travel either, but it seems children do, perhaps
because all their mates who are making longer journeys are getting on the
bus,