Everyone seems to scoff at the idea of staying in the ME >15 years whilst predicting little attrition.
Recently less scoffing and more staying. This area (with EK, EY & QR) is where the growth has been and the jobs are. Maybe the US will open up but don't count on it.
Has command really shot up to ~12 years already?
Not for people who joined more than a couple of years ago. But it will. See the next paragraphs.
Especially given TC is now talking about +350 aircraft fleet,
Based on that forecast a 40+ year old F/O joining now might never get their command at EK. With a current fleet size of 191 or 202 including freighters it would take a fleet size of 400+ before someone joining now would be up for command. Yes there will be retirements and resignations. There will also be DECs. Two thirds of the joiners in the last two calendar months were DECs. Admittedly a DEC spike, but they're not going to go away this time.
There are 188 aircraft on order. Half or more will be replacement not additional aircraft.
...and quoted recently as 120-150 A380's.
And this is where a part of EKs growth will be. Bigger aircraft equals more passengers (customers).
My advice is join EY.