User blog comment:Drek'TharSuperSword/What you want in the future./@comment-5792287-20130505125127/@comment-26531060-20130505153046

Because Miles is being like Doofenschmirtz; he starts with a tiny area that isn't even 1/5 of the whole (in Doof's case, the Tri-State Area, while in Mile's case, the Sonic franchise).

P.S: According to article, the Mario franchise is the best-selling game franchise ever, with roughly 450 million copies of games sold worldwide, while the Sonic the Hedgehog franchise sold approx. 85 million copies.