They had no such obligation. Speaking as someone who preordered the game, it was vastly more polished than many games out there now that took even more money. BF 2042, Cyberpunk, and let's not forget Star Citizen, those guys have raised over 420m and still have not delivered a game anywhere near the level of what NMS was at launch.
The major issue with with NMS was people's expectations and Sean's sharing of development ideas. But let's be honest, it's no where near the worst and they have more than made good on their promises. I'm with with @Diddums on this one. Gaming studios could learn a few things about customer satisfaction and making things right from Hello Games.
Oh, and they fixed all of it for free.
None of this detracts from the current state of the game. It's pretty impressive and bold. You can endlessly explore with no possible way to complete in you're lifetime. That's kinda cool.