You have already read all you need: reusable launch carrier being reused extremely rarely.
An experimental vehicle turning out impractical is absolutely normal. Usefulness is exceptional. (Even the SR-71 / YF-12 was scrapped. The Space Shuttle was scrapped, not soon enough.) But scheming to keep a program running anyway is extremely common. (E.g., again, Space Shuttle. And now STS.) Coolness (e.g. SR-71) is an inadequate substitute.
It takes solid evidence to demonstrate usefulness. In its entire absence, the correct conclusion is obvious.
To be fair the SR-71 was scrapped after being in service for 35 years, a point at which there where already multiple different much cheaper and usable alternatives.
SR-71 was awesome, but its reason for existing evaporated. Once it became easy to hit with a missile it could no longer be sent on the missions it had been uniquely qualified for.
An experimental vehicle turning out impractical is absolutely normal. Usefulness is exceptional. (Even the SR-71 / YF-12 was scrapped. The Space Shuttle was scrapped, not soon enough.) But scheming to keep a program running anyway is extremely common. (E.g., again, Space Shuttle. And now STS.) Coolness (e.g. SR-71) is an inadequate substitute.
It takes solid evidence to demonstrate usefulness. In its entire absence, the correct conclusion is obvious.