I'm pretty sure you are not part of the Elite:Dangerous community. The game is almost complete, playable, now. I have my complaints with the game, but the developers never had the attitude you're describing, in fact that is the exact attitude of Chris Roberts and his Star Citizen: keep buying our ships and hangars.
The E:D devs did state that some features will come as an expansion (e.g. planetary landings) but that was stated up-front. They never asked for more money to deliver a new ship or something.
What I think is they are under huge pressure to release the game before Christmas and simply don't have the time to implement & test a proper offline mode. As a note for those not familiar, the game already has a "Solo" mode, where you're online but don't interact with other humans, just NPCs.