It's changed a LOT.
There was a time when people out of their early teens didn't really admit to playing video-games. Older adults who came from a period before video-games looked down on it heavily. It was pretty much the social equivalent of saying that you still played with action figures. The people who did admit to it were those who got picked on by jocks anyway.
The funny thing is, that had kind of changed from years before, when the cool kids would hang out at the arcade. I think Nintendo's early attempts to define it as a kid's toy were a step back.
The PS2 was probably the first huge game-changer. Older teens didn't mind admitting they had one and pretty soon guys were talking openly about it.
The Xbox opened things up a bit more, then the flood-gates really came open with the 360/PS3 and the huge successes of Madden and CoD. I used to run a video rental store and we'd have all KINDS of people coming in to rent the big franchises. There were tons of kids who only cared about sports games, for instance.
Now you hear adults talking about video-games at work. I heard one of the guys I work with talking about Mass Effect and it turns out his favorite game ever is FF7. Another guy brought up Mario and then we were talking about what we've played on PS+. We had a group of us, adults, standing around talking about what games we play. That didn't used to happen very often.
The more gamers grow up, the more acceptable it is as a hobby.