If Starship starts to work as advertised, everybody else except maybe Blue Origin (if New Glenn also works as advertised...) will be out of the business.

The government backed organizations will continue as well, but commercial launch providers will need to find billions of dollars to build competing platforms without being able to start small and build their way up like SpaceX did because small boosters will no longer be economically viable. Blue Origin might be able to pull it off since their backer has very deep pockets, but their track record so far is dogshit so I'm not betting on them.