Out of about 1000 pilots I would hazard a guess and say about 200 are ex military which isn’t a lot really.
In terms of lifestyle and security etc... nothing much has changed in the twenty years I have been here. Still 750 hours/good pension/PHI/loss of licence/staff travel although the Airbus has been getting hammered for the past 18 months with 5 three day eastern seaboards the norm. That said the 747 was like that for many years. Everything goes round in circles over time and the arrival of the 350 will change things up. And before you ask, I have no idea how mixed fleet etc.. will work, and not sure management does completely.
As for job security people have been banging on about it for 34 years and we are still here