Starship Flight 7

SpaceX started Starship development in 2012. Despite 12 years of work, its best test flight reached space but not orbit, sending a banana to the Indian Ocean.

While NASA's SLS began in 2011 and successfully flew around the Moon in 2022.

Blue Origin's New Glenn also started development in 2012 and reached orbit on it's first flight with an actual payload.

When they say SpaceX is fast, what do they mean exactly?

The last SLS launch was in November 2022. The next one is in April 2026. That is 42 months between launches.

Starship may not go 42 days before the next launch. SpaceX's Falcon 9 + Heavy has launched on average once every 12 days since 2010.

And while Starship was "in development" since 2012, that doesn't mean it was prioritized. The first prototypes were only made in 2018.