They didn't just mess up, it was straight up false advertising. It was even found to be such in court in a few chunks of Europe iirc.
But no, it was very much intentionally deceptive, and that's why people were rightfully pissed off.
They HAVE put a ton of effort into making things right since release, which surprised me - my guess was they were gonna laugh all the way to the bank, dissolve their company and rebrand, and never push a single update for it. They seem to actually want to make the thing they promised, so credit where it's due, but the initial uproar was proportional to their crime.
there were a couple things that I hated about their overpromising on the front end; the uniform procedurally built worlds (there’s no real variety of terrain like Earth), the repetitive assets for structures (they’re all the same), planets don’t actually revolve around anything And you can’t fly between systems (they’re boxes, it’s not open. The only way from one system to the other is a loading screen hidden behind a warp animation).