Sequel or not, I still think it's DBE's fault for the failure of Astro Boy and the cancellation of Gatchaman and T28. For years, Hollywood has had a horrible track record of adapting anime into the big screen (Speed Racer, anyone?), but Imagi wanted to prove otherwise. However, since DBE came before Astro Boy, and since DBE had such a negative impact, it left such an ugly mark on Hollywood's anime adaptations, that less and less people won't notice gems like Astro Boy. Sure it's animated compared to DBE and sure it wasn't a masterpiece, but I found it to be more entertaining than Fox's poor attempt at bringing a well known anime to the big screen.
I think Imagi is very underrated.