After the Thomas Cook collapse last year, a few guys decided to jack it in and do either something they had done in the past or pursue something new. At least 2 have gone for financial services, a couple back to LA Instructing, consultancy for CRM and a few more avenues I can't remember. The problem is that not many alternatives pay even close to a SFO's salary let alone a Captains, but needs must etc. and I doubt many will miss the working environment of 21st century aviation.