Maybe the biggest hurdle for everyone except Starlink (with their standardized design) is spacecraft design and engineering, not cost to orbit?
And SpaceX’s Starship will be able to put a payload of 150 tons into LEO. How could we possibly make use of that capacity, other than Elon’s idea of sending millions of people to Mars?
SpaceX has lowered launch costs and they do launch a lot, but they're mostly putting their own satellites up. The demand from everyone else has increased a bit, but not really enough to support the "build it and they will come" theory.
The failure of the Falcon Heavy to generate demand speaks volumes about how much demand Starship will see, IMO. Sure we might get an occasional space station, big telescope or Moon landing, but that will add up to a handful of launches. The demand for three launches a day like Musk wants just isn't there, and won't be for a very long time.
Maybe the biggest hurdle is that having stuff in orbit has quite limited applications. Starlink is the first semi-reasonable idea that can utilize this much mass in orbit.