Sometimes leaving isn't as easy as everyone thinks. Being based near home or friends and family, stability of rosters, being near command and having to put together a dreaded CV all conspire to keep people where they are even if the grass is greener. Do you remember how much work is required to prepare for interviews? I spent 3 weeks researching two companies that I interviewed with recently and fortunately I didn't have to go to work. Try doing that on a 5 on 2 off (more than likely finishing on a late) or whatever roster.
Also there are so many Ryanair pilots that not all airlines are going to take them regardless of their jet time. The likes of Easy et al don't want to end up with a whole segment of their workforce being ex FR with roughly the same hours. Hence they mix it up a bit with CTC and other direct entry guys with differing backgrounds, cultures etc etc. I have no idea about the market for our mate in Rome and who is hiring or if the grass is in fact greener. He isn't going to head off and fly a turbo prop after being in a 737 after all. Plus he has the costs of the type rating to recoup and with so many other operators wanting you to part with money he might be loath to do so again.
Sometimes its better to stay in and try and hope that the T&C's change although I think we all know that with Ryanair that isn't going to happen quickly if at all.