Can anyone please tell me how counting the total number of stations one
could theoretically go to on one's journey can in any way be related to
the journey's cheapness?

Quite. It seems to me that the number of stations one can go to on an
Oyster single is one. You have a choice of which one but it is still one.
I am sure some other systems will have tickets that are valid for a fixed
period of time, e.g. an hour, and so can be used for multiple journeys.

G.