Yes, you are right there is something that keeps players coming back to early access games, in this case I think that it is promise that keeps people coming back. This game felt like it had promise during early access, but it hadn't yet fully delivered on it.
It took me 20 hours to get to the point in the game where I felt like I had experienced a lot of the content and could decide if it was a good game or not. Obviously the game isn't terrible or I wouldn't have put that much time in. But it wasn't great either, I kept playing hoping the game would build up to something, that I would get to experience the eldricht horrors hinted at throughout the game. But when I got there I found that the events were uninteresting and all that waiting had been for pretty much nothing.
So lets say it takes you 20 hours to decide if the game is good. The game has been in early access for over two years (2 years on steam at least, pretty sure it was available through their site for longer). It has had multiple releases in that time so maybe this user tried the game through multiple releases over a period of years. Sure if you take 60 hours and put it into a time block of seven and a half days it seems like a lot, but when you put that time over a period of years it's not really that much...
Besides, I don't think the reviewer was trying to say that they didn't get their money's worth (since they outright say they got their money's worth). They were commenting on the quality of the game.