And yeah, the instance where there are two lines of this are actually lines of slashes, the line of = is just one of several versions.
I do remember some old IDE (Metroworks on Mac? I barely used it) would recognize a particular comment style like this and create a kind of table of contents dropdown list, using these to break the list into sections. But putting them between every function would have removed the value in that too.
I never saw it in console work but that was all pre-Xbox. The Xbox was much, much nicer to program on than the GameCube or PS2 because it was all integrated into Developer Studio and fast instead of in some crazy flaky debugger. So a lot of places went to Xbox as their primary development console. As a result, I presume many recent console programmers are much less divergent from the PC-centric world anyway.
I hadn't seen those specifically at other developers, but I had seen a row of slashes between functions at a couple of other PC developers. I don't recall seeing them with console folks, though.