I don't see anyone catching up to SpaceX anytime soon. There are several possibilities on the horizon to catch up to Falcon 9, if Starship gets delayed for a number of years for example, but that seems unlikely. Competitors can continue to hang on via just the threat of SpaceX taking over the entire launch industry though but they'll basically stay minority players. That is until the cost advantages of SpaceX become too great and companies become large via using SpaceX to push their own business models.