The SBF is not something that is "created". All those phones that you mentioned all had SBF files that were leaked. The SBF is the original file that the manufacturer uses. Kinda like your windows CD. In order for the community to have it, it typically has to be distributed by Google (for Nexus phones) or leaked somehow from the phone manaufacturer. I know when I had the Droid X, we always had to wait for TBH to somehow get and SBF leak. We have to be thankful for the Dev community and the fact that they even provide us with Root. However, we can't blame them for something they have virtually no control over. It's like blaming Google (when you use Chrome browser) for not providing you with a copy of Windows when you need to get that from Microsoft.