its just a sign of the times. bikes were easier/cheaper to maintain and take less space to stable than horses, especially in inner cities. Trams (electric 'streetcars') were probably only just starting to spread in the larger cities.

There would have been quite a few underground train lines in london that would go on to become 'the tube', but in early 1900s mostly still slow and dirty steam trains, electrification was starting, but fairly slow to phase out steam.

The 1890s had seen a bicycle boom/bubble following mass production of the chain drive 'safety' bicycle and Dunlop's pneumatic tyres. Even in 1912 cars were very few and far between compared to bikes

Obviously cars were starting to appear, but i suspect many more bikes and horses were still on the roads.

The british expeditionary force in 1914 still had many cavaly divisions, very little of the army would have been motorised at the start of WWI. things like tanks were developed during the war so pretty unheardof in 1912.