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(I have a depth of ignorance which may become evident. Regardless of my ignorance, I will bumble towards what I think is a reasonable overall thought.)

The Soyuz has been the rocket and and spacecraft of the Russians going on almost 50 years, and I believe the date it will be replaced is 2020. That seems to show an operational thought in the Russian space program of emphasis on reliability and sticking with what works, while refining what has worked.

The American space program has never really had something comparable, and certainly does not at the moment. The closest would probably be the Space Shuttle, which was in use for 30 years (though it also had a knack of malfunctioning and exploding, so it wasn't that reliable of a workhorse vehicle).
Mercury, Gemini and Apollo/Saturn each lasted only a few years. I do know of plans to utilize those programs for multipurpose goals and to expand on them and perhaps make them dedicated vehicles, such as MOL, Blue Gemini, Big Gemini, the proposal to use Gemini to land on the Moon, the Saturn MLV, etc. The problem for Gemini and Mercury was, concerning utilizing them for different things like MOL, funding and NASA and the government not wanting to do those projects or canceling them. Concerning anything that might utilize Gemini as a dedicated vehicle and to land on the Moon, the problem was that Apollo/Saturn was the planned moon lander and future NASA vehicle, Gemini was viewed as simply the test bed for it and the bridge to it, and that plan never changed. And the problem for Apollo and Saturn was that when it came into being and NASA was extrapolating on it as the base for the (foreseeable) future of all space exploration, the public largely saw its mission as complete since the Moon race was won and the government cut funding and all future Saturn rocket and Apollo capsule production was cancelled and the program was cancelled.
That's where the Shuttle came in: a Low-Earth-Orbit vehicle intended as a support for the Saturn rockets, which ended up being the basis of the manned space program. And it became that because, to paraphrase Nixon, it's not good for morale for Americans to see out of work astronauts.

The challenge here is to make an American analogue to the Soyuz come into being: something that's used for decades and decades, refined and improved but always existing as the foundation of the manned space program. And what if that happened?
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