Game writing pays shit. Seriously. If I were paid twice the word-rate I get then as a full-time writer I'd still have to be guaranteed a 50K assignment each month in order to make what I'm making in my present job. On the upside, I wouldn't have to deal with VBA or the Windows API. On the downside, I'd be totally at the mercy of my creativity, which comes in fits and starts. I'd be at the mercy of my own ability to organise (people who know me know just how idiosyncratic that is). I'd also not get the volume of contracts that I need. I could shore it up by trying to sell short stories, but again: no guarantees.
So it's not something that I could do all the time, despite really wanting to. The on-again off-again nature of contracted writing is a blessing, really. And if/when I manage to marshall my time-management ability, some self-published stuff (possibly using a model like the one eyebeams came up with last week). It's something I do for love, not money. And that's a very good thing.