Oasis is a startup, therefore inherently risky for the younger pilots to join. Some of the retired ex-BA guys might very well switch, as they have some 2-5 years to go before retiremement. Having that said, high risk could bring high rewards and in the case of Oasis, it seems to be right. Some serious money is behind the start-up.
Over the long term GSS management will have to improve the conditions dramatically, if they want to hold on to their pilots.