I would say it is justified given the amount of support they gave the game in the aftermath, all for free. I would instead encourage people not to buy games at launch. Also, it’s not like this new game is totally different either from NMS, you can clearly see the back bones from NMS. So it’s obviously that they’re going to use everything that is good from NMS in their new game.
You should probably read up in the redemption of Hello Games / NMS. They have released update after update, dlc after dlc, all for free. The game is truly completely different from what it was. Not many games has gotten this good of a follow up after it’s rough launch.