The 'exodus' would be greater if RYR and by extention its pilots didn't have such a reputation. Every recruitment going has alot of RYR (and to a lesser extent Easy) applicants desperate to get out.
But by now we all know someone who works in that company and the crap they put up with beggers belief. Then there is other issue's like the rejection of a union, cadets taking work from experienced FO's, P2F, etc, etc,etc.
When it comes to recruitment, fellow pilots are usually involved somewhere in the process. When the going gets tough they might want to know that that they can depend on their fellow pilot colleague. They might not want someone who will shaft them and then say "well what else was I supposed to do if I wanted to get on with my career"
If you have enough money the low-co's maight be easy to get into but getting out might be harder than they expect.