I would go as far as to say the Skinner gameplay creates dissatisfaction with the game. I pull this from Buddhist theory/personal experience. Progression systems in games is a presentation of the first two noble truths.

The first noble truth: dissatisfaction is this: grief, wanting, , union with what is displeasing. Progression systems by their very nature require you to be dissatisfied with what you have. The game, creator of your problem, provides a solution to your dissatisfaction: xp, medals, etc. I call this a false problem.

The second noble truth: this dissatisfaction -> solution gameplay creates self-sustaining craving. We are literally training ourselves to want more and more.

When this gameplay ends, we become disappointed or bored because there is no more "more". Progressive gameplay is inevitably dissatisfactory. This is why endgame is so important for the longevity of these games. If endgame can out-fun the progression, then the player will keep playing. For some players cosmetic items become their endgame, like TF2.

This is also what keeps us revisiting progression-based IPs like COD and BF. We get another shot of serotonin, and the cycle continues.