If in every game there are 2,000,000 planets with an average of 12 creatures each, and the game needs enough creatures so that 3 people can play completely unique games without any of the same creatures, so that it stays varied that means we'll need 7,200,000 creatures on the sporepedia, considering the current number of creatures and the fact that the game has been out two days we can assume a rate of 300,000 creatures a day so far, if we continue this for another week that makes 2,700,000 creatures total. Then if we go at half that rate for 2 weeks extra that makes 4,800,000 total if for the rest of the time up to the rerlease, and assuming a 1 week period for most gamers to reach the space stage, that makes a total of 11,600,000 creatures by the time we need 7,200,000, which should maintain a much lower growth rate of demand, than content uploads. And we can also assume that 1/4 of the content on the sporepedia is undesirable, and this still leves plenty of creatures.

This shows we'll have probably enough creatures through a plausable model, the other content will always meet it's demand due to the fact that only the amount of sentient races already created by players will apear in your galaxy, and they will already have their own content.

Also something wich many people haven't taken into account, it will take you roughly 64 years to explore the whole galaxy, so therefore what is on the sporepedia now would probably tide you over for several years.

(I'm sorry if some of this is outdated by other posts in the thread, or if some of it doesn't make sense, i started typing half an hour ago and i'm tierd)