The fairing doesn't get carried to orbit. It's dumped as soon as aerodynamic loads are negligible. Since the fairing has the same energy requirement as the pay

The fairing doesn't get carried to orbit. It's dumped as soon as aerodynamic loads are negligible. Since the fairing has the same energy requirement as the payload (in energy/kg), it's important to get rid of it the moment it's unnecessary. If they took it to orbit (so they could leave in space), it would drastically cut down payload mass.