Because there is nuance to it. In example The Stanley Parable has a playtime of 1.5 Hours listed for "Main Story" and with some more playtime people get 3 Hours or longer, information based on https://howlongtobeat.com/game/14083 . A single run can take from a few minutes to 15 minutes, depending on what happens. After the game is "finished" in the sense of the "story" and the "achievement", it would have a similar playtime as the game of this post with the refunds. I have a few hours on this game too. But this is a bit open ended and asks to replay multiple times, with many endings and weird choices and different experiences, without spoiling anything (very important in this game). And the game costs 14,79€. Now this game is very liked by most its players, including me.
On the face value by just looking at the playtime and price, you would have to refund it. Let's say you enjoyed the game (its not everyone's cup of tea). Would you still refund it, after the 1.5 hours?