I think what the linked article was trying to say was something like this:
In an imperfect market, even goods that are generally not limited, can sometimes (locally, temporarily) behave like limited goods, thus increasing their price. We will call these unexpected extra payments “economic rent” because of their similarity with rent, which is defined as an income generated by owning a (truly) limited resource.
I think what the linked article was trying to say was something like this:
In an imperfect market, even goods that are generally not limited, can sometimes (locally, temporarily) behave like limited goods, thus increasing their price. We will call these unexpected extra payments “economic rent” because of their similarity with rent, which is defined as an income generated by owning a (truly) limited resource.