I think you sort of danced around something interesting, barely touching it. The correlation to technology is what got me thinking that as technological growth had light speed jumps during gen Y’s formative years, it would serve to compress the generational span. If you look at weapons, cars, computers, etc not a whole lot of innovation happened between the end of WWII and the end of Vietnam war. When we were born and coming of age, technology started making leaps and bounds(1980 here, but still a Carter Baby). We grew up with the internet as it evolved. People older than us were adults who had to adapt to the internet. People younger than us never knew a world without it. 1990 may be a bit long for Gen Y, but hey… they are made up! Right?