I'm not so sure that "getting the game you paid for and that's it" is necessarily a problem and not a feature. The deluge of DLC and season passes fragments online communities based on how much money they spent on their game, which I do not think is a very good selling point.
Regardless of whether or not the games appealed to me, I've been binding them to my gamertag anyways by "puchasing" them when they're free, then immediately canceling the download. That means I can download the title at any time in the future for free because I bought it during the promotion, even all the Xbox One games that have been available despite not owning the console. Sure, very few of the games were ones I have actually played/enjoyed thus far but you're referring to a community of millions of people with no common tastes. Personally, I hate sports games and have had no interest in the motocross/ATV games that have been popping up, but I'm sure someone is losing their @&*% over a free MX vs ATV game right now.
As far as PSN versus XBox, I heard that the PSN free games were basically rentals that you could only play during the promotion period, while XBox is giving you the full game to keep forever. In terms of value I think they're basically equivalent if that's the case, but I do agree that Microsoft is kind of scraping near the bottom of the barrel most of the time.