VEVO is a highly viewed channel - hence probabilistically their videos are going to be viewed more often and use more bandwith. Hence, YouTube caches them more

VEVO is a highly viewed channel - hence probabilistically their videos are going to be viewed more often and use more bandwith. Hence, YouTube caches them more heavily (and distributes them closer to viewers) as a result to probabilistically reduce video latency and cost of hosting. Same with any highly viewed channel - they all load faster than say something new with ~1000 views which hits a foreign data centre hard disk instead of a localised CDN server's RAM.