Concerning making money with proprietary debuggers, DDT (no, not that one) and Totalview are very expensive parallel debuggers of longstanding. Totalview has so

Concerning making money with proprietary debuggers, DDT (no, not that one) and Totalview are very expensive parallel debuggers of longstanding. Totalview has some form of reversible debugging and is unusual in not using GDB. They're actually rarely used in my experience, for various reasons -- not just because they're un-affordable for most sites.