This is the opposite of a monopoly, Blue Origin and Rocket Lab are both planning competing constellations. Eventually there will be many competing constellations in orbit delivering service.
>Government could be the creator
Okay so why wasn’t it? The lifetime funding for NASA is 700+ billion dollars. With that incredible sum of money they weren’t able to even make reusable rockets let alone the satellite constellation. Launching a constellation with NASA’s pre-SpaceX approach (using Russian rockets) would have been literally impossible because Russia could have never built nearly enough rockets. Launching even a small fraction of Starlink would have consumed the entire NASA budget several times over.
Comparing GPS and Starlink doesn’t really even make sense because the scope of each project is so vastly different. Starlink if delivered by the same people who made GPS, would have been literally impossible, because the mass to orbit is orders of magnitude larger than the GPS project. Starlink was only possible because of the efficiency provided by SpaceX’s reusable rockets and the leading minds in the government literally said that reusable rockets were impossible and impractical until SpaceX actually delivered reliable reusable rockets.