I see your point, and while having a job does shorten your attention span for games somewhat I caution you from falling into that trap. A lot of game journalists, developers, and media personalities focus their efforts so much on their work within the industry that they miss a lot of very important events and trends in gaming. They end up hearing about them second hand, and yet are expecting to formulate an opinion on it or even create works similar to it (or dissimilar from it). You end up with a kind of "ivory tower" effect, where you miss a lot of the game news and start to become disconnected from the pulse of the gaming community. I think that, in order to be a truly effective voice in the gaming world, you have to ration your game-playing time so that you can experience as much of what is out there as you can. Spending 200 hours playing L4D2 for the 90th time may be an enjoyable experience for you, but you're going to end up missing out on things that you're expected to know.
It just seems like a kind of weak excuse to me. It's like saying that you only read books from the young adult section because books meant for adults are too time-consuming and distracting from your job as an editor.
Basically your reasoning is sound, but if you want to keep up with the release-a-minute world of modern gaming and be taken seriously as a journalist, you'll have to put down the WoW account, take a break from LFD2, and maybe play one of the biggest releases of the year.