Not to defend this change, as I think it was poorly considered (my full thoughts at the bottom), and implemented even more poorly. But, to counter the above, the math is probably exactly why this change was considered. From a strict margin standpoint, there are solid margins, but when you figure in most of these credits pre-date the current groups purchase, the current ownership group isn't seeing those margins. Consider:
Assumption 1 - All teams are purchased at full price (rounding to nearest dollar): 24x$13=$312 per league. Prizes equal $46 for a single league + TOC portion adjusted to a per league basis of $14. So, each league in this assumption makes $312 and gives out $60 in prizes. 19.2% of league revenue given back to users.
Assumption 2 - All teams are part of a 6-pack and $10: 24*$10=$240, same prize structure, which means 25% of league revenue is now given out as prizes.
However, we know neither of these are how things actually play out. Most OLs are filled with owners who continually put in similar teams and earn credit after credit after credit. Theme league creators get their own credit, which means TL pay a larger % back to users than OL, and the most popular TL are the TOC advantage style leagues that help the same group of owners earn more credits. Roughly 50-60% of OLs are filled with owners who have teams in virtually every OL. Even if only half of their current purchases are paid with credits we get the following:
Assumption 3 - 50% credits and 50% full price (12*$5)+(12*$13)=$216, and now we're at 27.8% of league revenue for an OL going back to users. For a theme league this is approaching 34%.
Now, when you factor that *ALL* current credits pre-date current ownership, and several owners have enough credits to play free for years, plus the overall userbase is dwindling, meaning the share of credit purchases is increasing, it very well may be that in TLs, these numbers approach closer to 75% of teams paid with credits where (18*$5)+(6*$13)=$168, meaning 44% of league revenue goes back to the users....
With a robust userbase, this would fine, as the distribution mirrors closer to assumption 1, but as things currently stand, the above may even be understating the impact and % back to users might even be above 50%.
To be clear, I think this change is horrible. If the “vast majority” already fall in this range -- as the announcement says -- why would you want to limit/hurt your power users. This is basically just minimizing how many teams players like contrarian, ozo, ribbentrop skunk, mensu, gonoles, and a few others buy and use. While that impact is really only felt by a small number of users, it's essentially just the sites biggest advocates and those driving the game’s continued adoption and growth. By limiting them, you've effectively killed what remains of the dwindling userbase and those that are still driving non-credit revenue. Also, if the "vast majority" quote is true, it only makes sense if it's true on a user level, not a team/league level, otherwise the math behind this decision makes no sense.