Why a carrier ski-jump should not fold

Would a folding ski-jump improve a helicopter-capable aviation ship?

No. A ski-jump is a heavily loaded structural part of the flight deck, while a folding mechanism adds failure and alignment risks for little recovered space.

Aircraft impose substantial dynamic loads while launching, so the ramp benefits from being an integral steel structure. Hinges and moving machinery would introduce alignment and failure risks at exactly the point where a fixed-wing aircraft needs a predictable surface. A ski-jump also occupies less useful helicopter area than the proposal assumes. Helicopters can operate close to a fixed ramp, whereas a ramp that moved or stopped at the wrong angle could wreck the launching aircraft.