Well nasa doesnt really build anything. Its all contracted out. This process is inherently longer than Spacex building what they need/want.
Nasa is pretty much dead in the water. The model they are working under doesn’t work.
And yet despite Space X innovations, California rejected Musk’s requests to add more rocket launches, with one of the reasons for the denial being Musk’s social media posts.
https://www.latimes.com/california/story/2024-10-11/la-me-spacex-coastal-commission
The model NASA is working under is "contract our rocket-building work to SpaceX". It's working spectacularly.
It's the same model NASA worked under to for Mercury. And Gemini. And Apollo. And Space Shuttle. And every unmanned spacecraft they ever launched.