Comment by PaulHoule

Radical in terms of economics, but also radical in its incrementalism.

Falcon 9 was a highly competitive rocket without reuse. If they didn't get reuse to work it would have been a successful project. Reuse of the first stage was a huge cost optimization that put it in a class by itself -- but they they did it radically reused risks.

Contrast that to the X-33 which would have required a large number of new technologies to all work to fly at all.

Fixed-cost pricing was also a radical innovation because it drove SpaceX to do everything it could to lower costs. It was known for a long time that reusing (only) the first stage was a good path to lower costs, the SpaceX business model rewarded them for doing it.

SpaceX is highly technically innovative but it's been so successful because technical innovation has been centered around cost reduction and practicality, not chasing high performance for the sake of high performance.

The SpaceX model might need change to get to Mars because of latency. You can launch a Starship to LEO, have it blow up, and launch another one in a few weeks. If a Starship fails to land on Mars, however, you have to wait another two and a half years to try again. Similarly, SpaceX runs everything by remote control from mission control which is great in LEO but to stick a landing on Mars you need something that flies autonomously.