It's playable right now, has been for a long time. The fact that it's not been deemed "finished" is rather irrelevant. You can compare it to a similarly-themed game such as Elite: Dangerous, which has been released and updated through paid extensions. There doesn't seem to be that much more to do in that game, from what I can gather. (I bought it, but haven't gotten around to playing it much yet.)
Or put another way, with a typical funding method SC could have released their game a few years back as it was as "gold", and it would have been a decent game -- certainly no worse than No Man's Sky at launch.
Comparing SC to the average scam Kickstarter that doesn't deliver anything and lies to the backers is simply wrong. It's an ambitious project and their release date goals were way too optimistic -- but it's hard to get mad at them for that when you have any experience with software development.