You don't actually code in C++ do you? Maybe C++ has changed in the last 5 or so years, but otherwise the idea that a game written in C++ is more portable than one written in any other language, is absurd. When porting a game, it is usually rewritten from scratch by a different (ie more experienced on that platform) developer.
I dont really, not any more (not since uni), but C++/C# whatever, my point is they are widely used in the industry. I do know they (C++ & C#) are virtually a must-know for almost every (good) game programming job advert that i have ever seen. What i was saying about portability is if you are porting in the same language all the bits that actually talk to the graphics, sound, control hardware etc would obviously need an overhaul. However vast sections of the game code eg. the ai, game logic, event system, physics (if not hw specific) etc could remain the same regardless of platform. A conversion team is unlikely to re-write the entire mechanics of a game (unless they absolutelty have to), just the bits that need it. (Assuming its a structured program with good docs :)
That said, I agree with you, that if a games is good enough and they think its worth investing in they probably would without question, even though it would require a lot more work to re-write the entire game.