If you go back as far as the Constitutional Convention you can read in the minutes James Madison wrote of the constant fear expressed of a standing army taking over the government. That concern was drilled into generations of officers and became an overriding value for those pursuing a military career.
Meritocracy was a reaction to the British practice of the purchase of commissions by royalty.
So meritocracy is against obtaining rank for any other reason other than merit, right?
It will be foreign troops ready/sent to take over the US military.