I got to meet Raph Koster today. For those of you who don't recognize the name, he's one of the main guys behind Everquest, Ultima Online, and Star Wars Galaxies to name a few of his games. He is in town to give a talk at a game design conference that's in town this weekend, and he stopped by one of the classes for my graduate program to meet some of the students. He talked about how he got started making games on an old Atari 8-bit back in the day, and he then talked about how he prototypes games today. Apparently he uses Blitz Basic quite a bit for prototyping ideas, which is interesting because Blitz is a fairly cheap game development tool that's somewhat popular in the (PC) Indie community. I gotta say that I wasn't the biggest fan of his book (A Theory of Fun for Game Design) when I read it last year, but it's an okay read especially if you've never really thought about or been exposed to game "theory." Still it was pretty cool to meet one of the guys responsible for some big name games.
He didn't go into that in a whole lot of detail, but yeah I would suspect so. Most of the "bigger" developers I've met usually have their own engines built using C/C++, although I do know a few smaller developers who have moved to C# and a lot have also moved to various forms of middleware commercial engines.