Okay, scroll back and quote me, where I say: It can't increase. Or more specifically, I don't think you are fully understanding what I said. For one thing, laws of logic are always true. The law of diminishing returns always applies. What it says is there some point, which you can represent on a graph. in fact let me google a graph up >.>
As it relate to football, and zeek specifically, the number of carries zeek gets at first leads to an increase in his YPC. His yards increase during this part. However there is a point, the point of diminishing returns, where once you hit a certain number of carriers Zeeks YPC will start to go down. Now this point of diminishing returns is different from game to game and season to seasons. Things that can effect it are things like defenses worrying about Dak on season and then not the next season. Age. Injury. Good Defense vs Bad Defense. Strength of schedule. But there is always a point of diminishing returns. It is just not always at the same place for every game. That is why its hard to compare week 13 to week 14 sometimes because you could've played the worst defense in 13 and the best on 14. But that tends to average out at the end of the seasons because of sample size, letting you compare running backs and say why Zeek's YPC is lower than such and such, because Zeek has been a workhorse. Also, when you are trying to prove your point, you are doing it using the season as a whole, instead of game by game, saying that Zeek should have lower production, because on the season he had many carries. Where in the stats I was looking at, zeek where he had his highest YPC at the end of the season, for that game, had his lowest amount of carries. A season does take it toll, but zeek hadn't been abused enough to take away the advantages of the rest between games. So in turn, each game is what we look at when we say that Zeek will have a YPC for that game, if he has lower carries, but in turn he probably will also have less yards than he would've if he had increased carries but a lower YPC, since he is still gaining yards even when his YPC is decreasing. As for the article saying, "In General" Well I think debaters and writers have a certain sense of carefulness, and say things like that, so that their point still holds when someone comes up with some obscure example. The general concept is simple, but in actuallity it gets a bit more complicated with many variables effecting where the point of diminishing return is for each game. It isn't always obvious when you look at two games next to each other either, since you would have to research more in dept and compare how your team did against a defense versus others.