Why new?

Hi guys, I'm not sure if I should have started this topic here but I have a question for you,
---Why was a new series started(i.e Metal Fusion etc)with new protagonist(Gingka and co.)
why couldn't they keep Tyson and co.?
because thiss new sereis is better and good graphics no need for this thread
^That really isn't a reason.
But you should search or ask in the Anime questions thread ..