Every packet traverses multiple such core routers (most likely from multiple internet providers), so 1 Tbit/s from A to B requires many more Tbit/s of actual ha

Every packet traverses multiple such core routers (most likely from multiple internet providers), so 1 Tbit/s from A to B requires many more Tbit/s of actual hardware capacity sold. Or take the edge capacity of small FTTH providers and you get to quite large theoretical numbers too. Hundreds of Tbit/s easily if one is offering Gbit/s or faster service (my ISP has around 1Tbit/s of equipment installed just to service around a 300m radius of residential homes). Both are true for Starlink as well: In case both source and target are not visible to the same satellite they have to be routed via multiple hops or sent upstream (ground station) to the rest of the internet. The edge capacity (RF up/downlink) boasts insane numbers, but the actual internal backbone is much more limited. For consumer it is less of an issue since they won't mostly fill up that 1Gbit/s service they have, but businesses will absolutely fill that up (so you can oversell much less). Starlink doesn't have nice overview of actual specs of future satellites, so I can only use what people have figured out or what they have published. But you are right about the number of satellites, I looked at the wrong column (it was for phase 1 and not 3), so density will indeed be much higher, so from that perspective it will be somewhat more capable (depending on fast/slow their rollout is). And it's not clear if it would actually be cheaper for SpaceX to have such customers (since some of the traffic would go to the rest of the internet - requiring ground station resources) or go elsewhere on the planet (filling up inter-satellite capacity), but that's not too much different from how regular ISPs have to plan (some customers are cheaper for them than others).