Historically the time to upgrade in the legacy carriers for a long haul spot used to be just that, 15-17 years! Sometimes even longer.
I know this from family experience, my dear old Dad was 17 years in the rhs in BOAC before his Command. His course lasted 12 months with every sector being assessed in the most minute detail, as well as his deportment and dress whilst on layovers!!
Now I know times change, however, it would be strange if the Upgrade policy was NOT changed in line with the ever changing company entry requirements. After all historically everyone coming to EK had had a command before arriving.
Without doubt IF the age bar comes in , it will be a serious blow to those caught in the fallout zone.
Though it must be said, and I stand by with my tin hat for the fall out incoming,
there is a measurable difference in maturity between those pre and post 35.
Maybe it is the arrival of ankle snappers, the loss of the flush of youth or even the arrival of one's first grey hair(or loss of one's luscious locks!!).
Let us remember this is a very serious business, as 521 is a timely reminder.
If the owners of the train set want to change the demographic in the LHS it is their prerogative, it is also their weight to bear when and if a whole age group resigns en mass.