You also need to realize that having people create a ton of communities benefits Steem holders. They need to hold Steem to utilize them. Raising the cost will ultimately affect the potential value of Steem.
You have to consider competition as well. Why come here and pay to create these communities when they can do it on Reddit or elsewhere for free? Sure, you can make a little money. But, it's not easy and the money made by most people on here isn't enough to keep them here. Just look at the amount of active users here. Not very many.