GDB development is driven mostly by Redhat and Mentors Graphics (ex Code Sourcery), and both of them often add new functionnalities, fix bugs and maintain GDB. But maybe their work is at too low level for most people to notice?

I still wonder what's missing in GDB. I got quite proficient with this tool, and never had access to VS. I personnally don't count GUIs built on top of GDB, as they don't provide new capabilities, just 'fancier' interfaces that GDB's CLI.