I think what most of the commentary is on is the initial gameplay loop which has to do with planetary exploration and learning words. After that there's a multitude of new gameplay loops that become intertwined. I don't think most players get that far unless they have a very old account.

I think it comes from a difference in what people want. Some people want to achieve goals, while others want to be given tools to be creative. There's a whole spectrum in between, plus other motivations as well.

I enjoy being creative to an extent, but I like to solve problems, so I naturally gravitate to something with a long-term goal to achieve like Factorio (I rapidly lose interest after launching a rocket though).

Saying the game is a space sandbox and then implying that the inability to find fun falls onto the player's inability is what every online NMS fan says in discussions about not enjoying NMS. Calling a game a sandbox doesn't spawn game mechanics into existence, the game is still limited by what the devs put into the game. Your goals are still limited by what the game provides to you.

But a game can have 1000 hours of collectables content and still not be an enjoyable game to people. For example, I don't really enjoy collectables purely for the sake of collecting or building without having some sort of meaningful functionality. Every time I've tried to get into NMS (and when I ask others about what you can do in the game), I get the impression that 99% of the game is just flying/walking around, scanning things, collecting some random doodads, base building, and hoping to find a "cool" ship in a station to buy. Which is to say, the same things every base building survival game has, but in space.

I don't necessarily need forced goals, but I need things to work toward that aren't just collectables. For example, in certain other space sandbox games I can build up or destroy political factions. The universe around me dynamically updates in ways that actually affect me meaningfully. I can build up industry to harvest resources, refine them, and produce various goods either to use or to sale. I can have a goal of building all of the infrastructure needed to produce ships, or colonies, or what have you. With a larger industry, maybe some of the political factions try to attack me, so I then need to defend against them. I could build up a fleet of ships that handle defense and transportation of resources. I want to feel like the universe actually responds to my input.