Sure, there are competitors. Starlink (or any other proposed LEO constellation) offers a fundamentally better product as a result of low latency (ballpark 640ms vs 20ms). Which they get as a result of being in low earth orbit instead of geosynchronous orbit. Starlinks costs per unit bandwidth are almost certainly far lower, meaning the ability to out compete on price.
I don't see the existing constellations remaining competitive for long.
I don't see the existing constellations remaining competitive for long.