But Ratchet and Clank is legacy Sony IP and is the 'safety net' for Insomniac (meaning that if Sunset Overdrive and other projects fail, they will always get something out of this series), so they must want to show that game off.
Also keep in mind that the series hasn't been in the greatest shape for the past two or so years. All 4 One and Full Frontal Assulat while (reportedly) solid games, were no where near the quality of past Ratchet and Clank games. Sure, Nexus came out last year but that game was so short and was pushed aside for the PS4 launch (one must question why that wasn't a PS4 launch game :l; the game clearly struggled to run well on PS3 with its frequent Frame Rate drops, so it being moved to PS4 as a big PSN launch game next to Resogun would have been a smarter choice).
With the PS4, the series has the chance to be 'big' again and once again be Sony's Mario/Sonic; many younger games must have gotten PS4's last holiday and there are many PS4 owners who grew up with the PS2 and PS3 games, so having a full-on, proper Ratchet game on new hardware has the shot at huge success
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