Here's why:
* Exclusivity: The *Ratchet & Clank* series is a PlayStation exclusive franchise. This means Sony owns the rights to the characters, story, and gameplay, and they generally only release them on their own platforms.
* History: The series has been a flagship franchise for PlayStation since its debut on the PlayStation 2.
* Success: The *Ratchet & Clank* games have consistently been successful on PlayStation, giving Sony no reason to break the exclusivity and risk losing potential revenue.
While a *Ratchet & Clank* game on Xbox is highly unlikely, it's not completely impossible. However, it would require a significant shift in Sony's strategy and a change in the franchise's history.