>>717543092
It's definitely a business decision in hopes of expanding the audience, they believe the established fans will stick around no matter what by keeping the old characters in the wayside while new fans will come over with the new characters.
It is always a gamble, never guaranteed to work. With Devil May Cry the only thing I see is new people actually looking forward to Dante, and now Vergil, more Nero by a significant margin, so yeah, depending on the IP the original protagonist just can't be replaced.