Definitely looks like there’s a bug for the category count.
Also, Magento Connect is broken down into license type, Commercial and Open Source:
There’s actually no commercial extensions right now though, but where are you seeing an extension that isn’t free?
By the way, Magento can’t force the extension makers to keep their product free and open source, it’s entirely up to the developer.
As Magento evolves, there will be more extensions added, but it’s still a very young product. Version 1 literally just came out, while osCommerce has been around for 8 years now.