The early carrier gap was a money decision

Did the Royal Navy remove carriers because of a study about force needs in 2020-2030?

No. The carrier removal came from an SDSR money-saving decision rather than a strategic study that proved carriers unnecessary.

The decision was driven by a desire to save money and the political appeal of cutting something critics could call a white elephant. Britain still needed some form of aircraft carrier if it wanted to project power from the sea. The resulting gap was a budget expedient rather than a coherent force-design choice.