geographic and EBG lock for 6 months is huge. Tie that with LAX is small and not a lot of open time for reserves to get used plus always a new hire coming in that soaks up those lines and OAK being a PIA commute to the east coast and it's a no brainer. Age might be a distant 2nd to those constraints.
I'm also assuming the majority of those bypassing are getting close to upgrade in their/more desirable base. I predict bypass comes down to 600 by spring.