I read somewhere that during the early years of the US government, well into the 19th century, the govt was very wary of such a military caste getting established, and many well qualified individuals were denied commissions because their fathers/grand fathers/other immediate family had held commissions.
No doubt they were wary -- in fact, that attitude persisted well into the 20th century at least - for example, while he doesn't explicitly call out family dynasties and the military caste, those concerns clearly inform Eisenhower's thinking in his famous "military-industrial complex" cautionary speech:
