Let me tell you how things work in the film business...
Money.
Astro Boy didn't get enough at box office because of poor advertising. Dragon Ball Evolution despite not being good got a Gross Revenue of $57,497,699, the budget for the film being $30 million.
Astro Boy meanwhile had a budget of $65 million but only got a Gross Revenue of $44,093,014
Films need profit for a sequel, if there is no profit then what reasons will the film makers have to make one? They won't take a risk in doing a sequel that might make them loss more cash that they don't have. If it's ever happened, then i've yet to find it.
It doesn't matter how many people say liked the film or they became fan of the series from watching it. At the end of it all, it's money that decides everything, wheither the film makers did it for Astro Boy or not.
Don't take my harsh outlook as one of criticism. I love the film a lot. I don't care if it's not Tezuka made and I don't care if it doesn't stand true to the original series, it's still my favourite that I wish Tezuka
HAD played a part, maybe he would've made the story something even greater...and would never have let President Stone come into existence

The fact Tezuka Productions are doing a Pluto film is a good sign, that they're taking another shot at bringing Astro Boy over to the U.S. if that goes down well, then there might be a chance of a CGI sequel happening, maybe.
Despite the few things that could've run different, I love the film and I don't want to see another Astro Boy adaptation replacing it just yet. I liked the new Astro they created in it, having him older was a good idea because it made him easier to relate to, and I like the universe he was housed in. I want to see a new chapter to that, what else could be in store. The whole film was about Astro becoming Astro Boy, and he did right at the end, but what comes after that? The story just feels unfinished leaving it as it is. Even if it was a direct to dvd release I wouldn't mind.
As for the characters Elefun was strong, though Tenma wasn't like the 03 Tenma he had differences to the other past Tenma's that I liked since the film's message is about family and he carried that well. Zane, Widget and Sludge could've done with more character development, but Cora wasn't so bad as a love interested (Astro's had so many over the 60 years) out of them all, to me she's the best, she wasn't invented as a damsel but a tough girl, somebody that could take care of themselve (because frankly seeing a women portrayed as a weak individual in flimsy clothes while the men are the lone tough fighters annoys stuffing out of me). I'm actually sad she's not an official character in the series because I'd love to see more of her and not some other future stand in's that are bound to crop up in the future.
But...you're right, it wasn't a bad film, I rarely can watch a film so many times as I have for this one. And if it weren't for this film I wouldn't be into the series now. I wish Tezuka Productions and Imagi could see the positive outcome from it and that they've done some good in their attempt to spread Astro to the world as Tezuka would've liked. They
shouldn't go sweeping this one under the carpet, pretending it never happened. v_v