I am almost 43. I vote I have never given a hostess gift. I'm not quite sure that is true, because I did take a bottle of wine to a party once, but I think that was technically a birthday celebration.
I don't really go to parties. When I was growing up, it seemed like things were pretty no nonsense. I understand the concept of dinner parties and the like, but we just never did these things in our family. We would go to birthday parties as children, and of course we'd bring a present. The parties were very proscribed--you dressed nicely, brought a gift, ate cake and ice cream, played pin-the-tail on the donkey and left with a hat and blower. Parents didn't come, you went when you were old enough to know how to behave, and these parties were pretty much done by the time you were 9 or 10 years old.
Sometimes we'd have family over for Thanksgiving, and people would bring dishes for the dinner. Or maybe a backyard cookout, and someone might bring chips or beer that they wanted to drink (my parents didn't drink). In general we didn't go out to eat but maybe once or twice a year, we barely went into people's homes let alone go there for dinner. I know my parents did some socializing with my mom's sorority, but the kids were left out of that, and they were usually going to a public place, so there was no bringing of a gift.
The idea of going to a party and bringing a hostess gift is just something that seems like it's for people in books, or something.
Like for people in a different social strata than the one we were in. Plus, when I've wanted to bring something, like a bottle of wine (which I've heard of people doing when they are invited to dinner, that seems normal) or a gourmet kind of treat, I'd be afraid that the person would not like what I was bringing and wonder why I was bringing it. If they didn't serve it, I'd think it meant they didn't like it, but then I wouldn't know if I was supposed to serve something given to me as a gift, or if that would be considered offensive. It seems like a potential minefield and kind of scary to me.
But now that I know it is so common, maybe I'll think about this more. Not that I go to parties.
I think part of this is that I grew up with parents who were both raised during the Depression. I have nieces my age who have Baby Boomer parents, and their experiences are a little different. I guess it's not necessarily an age thing, but just a custom thing, and I'm not really familiar with the custom.