Pretty much the same problem the military has with their current sniffing around at Starship. Sure, you can deliver 100 tons of cargo to remote Syria in an hour, but then you basically just have to leave the ship there to be buried in the sand. Starships will be cheap, but they're not free.
When Musk made Falcon 9, Russians said "it is the same as Zenit, only with very old engines".
But in reality revealed, that to make re-usability with reactive landing, need extremely wide engine throttling diapason, because starting with very big weight and need max power, and landing empty, so need very little power.
Musk solves this with 9 engines, so only 3 used on landing. Russian Zenit is incapable to make so little power to make reactive landing on main engines.
No, Starship, or to be more strict, Musk proposal is very different. First, already existing hardware have much less energy dense. Second, it's engines use another fuel, also much simpler to handle.
Once I hear idea, to make for S-5 additional "zero" stage with displacement feed engines, and this would be necessary simplification, to make subject idea viable, but it never happen.
In 1960s defense industry tried to save money flow with such projects.
They had huge troubles, because after 1940s, military spending's constantly reduced, so defense industry have to cut workplaces, some firms just closed.
But there was unpredicted sequel. In 1990s, Russians spend few icbm's, to deliver few hundreds kilograms of mail to Canada. - They have made special container with parachutes and placed it instead of warhead. Then the rocket launched, and in some 20 minutes container got down to ocean about mile from Canada shore.
> after 1940s, military spending's constantly reduced
I think your information is incorrect. There was this thing called 'the cold war'. From 1948 on military spending constantly *increased*, when this report was written it was already 200% of the 1948 level.
For people wanting a summary.