If my reading comprehension skills have not utterly failed me, the abstract says "people who buy a service frequently, find ways to cut out the middleman. This happens more if middleman fees are higher".

In about 25 times as many words. There is no hope for tech progress when this much time is being wasted.

Besides, transaction costs have been thoroughly explored in economics since 1970.

Abstract is not (only) the main finding of the study. It’s often a mini version of the article, with a background, methods, results and conclusion.

The length of the abstract in the linked article is well justified, in my opinion.

I understand that the point of an abstract is to tell a researcher in the field whether or not the paper is worth reading. I don't think the authors of this paper understand that, though. My reaction was "well, that's two minutes of my life I won't get back."