Something I just thought of while reading about the hilarious Olympic-Titanic insurance scam conspiracy theory: Do we know the plans, if any, that the White Star Line or IMM had between 1912 and 1914 to replace the Titanic? The Cunard and Hamburg-American Lines would have their own three ship services ready by 1914-1915 while White Star would be left with just two major express liners, Olympic and Britannic.
Whoops. Misread this.
From what I currently understand, Olympic, Titanic and Britannic were put into service to replace a few older WSL liners, Titanic specifically replacing Georgic. When Titanic was lost, the liner intended to be retired simply remained in service.
There was also another Britannic planned after the First World War, but these plans never came to fruition. The Olympic Class Britannic (the second WSL ship to bear that name) was the largest they had ever built and it never even saw a paying passenger.