Re: What's happening with bbPress?
We invested in bbPress since it was open-source and we could take it whatever direction we wanted. I would recommend the same for those here worried about future support (if you like the product).
If you still want to move to another forum software, I would first pick a new platform… and then find out if they have a import utility. If they do, find out the format of data required and build a script to dump the data from bbPress in that format.
If you are not able to do this yourself, hire a programmer. Someone fluent in MySQL and php/perl should be able to pull this off fairly easily.