We're not talking wider gene pool, were higher generation crosses with a modified subspecies. This is somewhat different as original sterile flies were designed

We're not talking wider gene pool, were higher generation crosses with a modified subspecies. This is somewhat different as original sterile flies were designed to produce low viability first crosses. It remains to be seen if they're more or less robust. Any outcome is possible. They could also be more or less fecund. They will be harder to kill off via an engineered program like a disease or maybe sooner insecticides.