Interesting... I've had a Virtual Boy for years, and I honestly can't say how long the batteries last. I was just thinking that they always seemed to last forever in mine (like months), but then I realized I've never even dreamed of playing the Virtual Boy for anywhere close to an hour straight. In fact, twenty minute sessions at a time seem kind of long. So maybe I was just kind of slow to wear mine down.
I owned the thing as more of a fun piece of history than something I was really interested in playing. It was donated to some church yard sale and given a $5 price tag, I stumbled upon it and scarfed it up. This was about a year or two after the thing came out and failed miserably, at the time the things sold for about $25 used, so it was a steal. I remember at one point Toys R Us had elaborately stacked piles (think grocery store canned food ziggurats) of the things near the entrances of their stores with large clearance signs towering over them. Those stacks were there for months and months.
It is funny to think that something you couldn't give away at one point now sells for more used than they sold at retail, and far more than the clearance price Toys R Us was still unable to move them at.