I am aware that everyone has a differen't threshold. So yes you are right there is a sweet spot. I am telling you that right now we have a certain amount of players, and a certain amount of user abuse. Lower the buy-in you may have more players, but you will also get more user abuse. User abuse doesn't have to mean cheating either. More people will just bail on teams, more people will try and tank seasons, or just check-in once a week etc etc etc. The cost helps keeps people invested in their teams. Raising the cost would generally have the opposite effect. There would be fewer people playing, and those who did would generally take it more seriously with fewer user abuses. Also if the cost was increased too much more I would expect WIS to take some basic precautions to protect against aliases. That would never stop cheating entirely, but could make it inconvenient enough to lower the abuse rate even more.
My guess is they have already analyzed how much they can charge and at what point the returns start to diminish. $25 is probably pretty close to the sweet spot.
I was unaware that we were paying "stakes"? We are paying to enjoy 3 months of a simulation multi-player video game. The credits are just to keep people around the site longer, and have a larger incentive to try an win it all. Stakes imply that we have a chance of winning real money like gambling right? Why would WIS want some folks to get to enjoy the game for $10 while others had to pay $50? Why wouldn't even the best worlds just go into a $10 world and enforce their rules just the same?