0497 a good analysis to which one could expand as a geopolitical one.
The US indeed tried to operate as a land orientated military system after the 1st World War and only after the Washington Treaty did they try and level the playing field with limitations on British sea power.
Europe, although largely regional in its composition, like the States in the US, does have an extensive littoral and plenty of natural harbours. As a USE if it needs to trade globally it may, like the USA, realise it needs a global power projection capability; the geo-political aspect.
Which country builds the components of that system, be it aircraft carriers, transport aircraft etc is part of the argument and is probably no different from the pork-barrel system in the US, just less mature. We certainly don't like ceding ship construction to other countries but we cannot escape the fact that Norway builds tankers, Italy cruise ships German, Netherlands etc, all build warships. Even if we could agreed a standard design of warship we could certainly build in several yards at once.
Political will, modified by geography, will drive the shape of a European Army.