Starlink is normally a single hop from a home to a satellite and then down to a base station hooked up to fiber. To work over the ocean you pass messages between satellites potentially several hops and then eventually down to a base station, but that’s inherently constrained as with all mess topologies you get far less bandwidth than initially seems possible.

So in part it’s overhead to deal with inefficiencies and in part it’s a limited customer base for a lot of hardware, but it’s also just what the market will bare.