Wish I had the skill Joe, it's a niche real time area of programming where you need to understand the GPU in detail and you probably also have to understand proprietary Graphics libraries intimately as well.
Once upon a time it was possible if you were a generalist but now you have to seriously specialise if you want to get into games and a huge part of the real development is done by artists now not programmers.
Real time state machines at the bottom of the stack, I can do that stuffbut the high end graphics are hard
You asked the question in past tense and I did not really answer that, my career in IT has been pretty random, I really drifted from one money making opportunity to another, if I had been focused then maybe I could have got into the interesting stuff but I wasn't, the thing I really missed out on was a chance to get into CRM development in the late 90's I had some friends that made a fortune in that field.