Why four G3s and four N3s were only Britain's opening move

Were four G3s and four N3s enough to match the planned American and Japanese capital-ship programmes?

They were an initial five-year programme, likely followed by successor groups rather than Britain's final answer to the arms race.

British plans covered a shorter horizon than the decade-long American and Japanese programmes. Later groups of G3 and N3 successors could bring Britain to about sixteen new ships while it retained thirteen modern capital ships as a baseline. The fleet would also adjust to what rival navies actually completed rather than every announced project. Lexington belonged to a different comparison because it was designed for reconnaissance and cruiser hunting, not to fight G3s or form the fast wing of the battle line.