Thrustpig: I'm with you on what you say, but it is a case of Supply Vs. Demand.
LCs demand the best pilots as many have taken decades to build their reputation. A serious incident can wipe out all that hard work in a flash of a news headline. So for these top notch pilots they have to pay well.
LCCs knows at this point in time there are a lot of good experienced pilots kicking around looking for work, so market forces dictate that salaries can be set lower.
Give it a couple of years, as airlines expand and there will be more pilots retiring than training up, market forces will dictate that LCCs will have to raise pay to hold onto vital experienced flight crew or suffer the consequences of poorly qualified ones.