The owner/lead developer (I don't know what position exactly Sean Murray holds) straight up lied about features in NMS (e.g. multiplayer) that weren't there nor will be ever added so I'd say it was a scam.
The evidence largely points to a developer who is good at his core job, but inexperienced at managing hype. And who was overly optimistic about what he and his team can accomplish in X amount of time. Based on how Hello Games is acting & communicating now, I think they've learned their lesson.
And I sympathise a little with them because I was once the overly optimistic team lead in my younger days, and had to get burnt a few times before I learned my lesson.
In video game development, studios are frequently forced to cut significant content or features from a game for a number of reasons. That's why the smart studios are pretty cagey about promises until they're VERY sure they can deliver them. Sean Murray was reckless with his promises and that's what got him into trouble.
It's possible he outright never intended to deliver those features but I don't think that's the case. It's clear they tried very hard to deliver as much as they could.