DC's tried to do different things with them over the years, but I think the main problem is that these characters were born under 90's continuity from a different company entirely. Image fans and DC fans don't tend to be an overlapping base, so I can see fans of the different WildStorm books not even realizing these things happened until it's too late to do more than pick up the back issues, while the DC readers may recognize the Gen13 cameos due to that title's re-launches, they may not have any idea characters like Grifter and Warblade have 20+ years of history behind them too because they weren't Image readers back in the day.