Is EasyJet supposed to be the British equivalent of Southwest? From some baffling facts I read about Ryanair (in a US flight ops. publication), it could not be that one...
Maybe there is not a valid comparison, but I worked with and know one pilot who left Southwest (he earned the free type rating in a Navy squadron), as he was hired by another airline with a crewbase much closer to his hometown. He was laid off, but has a desk job with the Navy.
To leave Southwest is quite rare, except for those who retire. Right now, post 9/11, it is impossible for me to imagine.