I hate to further provoke a thread that has covered ground done to death many times before, but on the whole age issue, one of the major plusses for "older" pilots is something which OBK highlighted as a potential negative, i.e the whole wife, kids, mortgage thing.
For any airline to part with the vast sums of money required for sponsorship, there are many things they want to see which have already been covered. Another one is long term stability. This is why so many airlines require bonds. The "older" pilot already has a more stable lifestyle and is more likely to remain on a long term basis than a younger, single pilot (in general - everybody is different and I don't pretend otherwise). We can't afford to take the gamble of chasing around from one job to another once you have other people to consider in the equation.
All recruiters want to find the ideal candidate, but often have to compromise. With young pilots, it is the risk they will up sticks and leave for another company/career, with older pilots it is the shorter remaining length of service.