Besides what 55555 said, in the near term SpaceX has indeed passed at least some of the cost savings onto customers. NASA administrator Bill Nelson quoted a member of the Joint Chiefs as telling him that SpaceX had saved the US government $40 billion for just launching military payloads. <https://www.fool.com/investing/2022/06/05/did-spacex-really-...>
On the civilian side, SpaceX saved NASA $2 billion for just one payload, Europa Clipper <https://arstechnica.com/space/2023/10/a-year-from-launch-the...>, so who knows how many billions more from other launches.