Elon Musk

[AFTT47]

.A practical orbital system where the booster is routinely and reliably reused at economic benefit is something most engineers thought impossible. When starship is operational, it will reduce the cost of lifting heavy loads to orbit ten-fold.

It should be noted that the SRBs for the Space Shuttle were reusable and reused.

Yes indeed. The 3 liquid-fuel main engines were also refurbished. Of course the orbiters themselves were reused. Here were the problems:

No money was saved by recovering the spent SRB casings. Indeed, it probably cost more to recover them and prepare them for receiving fresh fuel segments than to just build new ones.

The 3 main engines required extensive refurbishment and took a lot of time to be accomplished.

The orbiters themselves were labor intensive because of those damn heat shield tiles. They never did get that problem really licked.

In the end, the shuttle ended up being enormously expensive. It cost about $1.5 billion per launch compared with about $68 million for Falcon9. That's 22 times the cost! Part of the problem was the way the government works. Multiple agencies with multiple (and often contradictory) requirements had a hand in the design process. Different components were built by different suppliers in different states (all looking to get the votes of different senators in the approval process). The reusability of the shuttle was little more than optics. It did nothing to reduce the cost of space operations. In fact, it was probably the shuttle program that poisoned the aerospace industry against the idea of truly practical reusability in the first place. It came to be seen as a fantasy and a scam.