I think that many people, even with all the gameplay videos posted, just don't understand how it would be like playing this game. I think that most people are more excited about the things that weren't revealed - let me explain. I think that because of the mystery that Hello Games create surrounding their upcoming title, it makes people imagine things, they create fantasies, but at the end of the day, this is an exploration/crafting/survival game, simple as that. I don't expect it to be anything more than that (OK, maybe a multiplayer mode in the center of the galaxy.. LUL). If you like these type of game, you'll love No Man's Sky if you don't you get bored with it pretty fast.
I think that many people that never played these type of games will buy it because they want to experience that amazing new procedurally generated world working in front of their eyes.
I personally prefer a small-scale world full of activities and most of all, playing with my friends. It holds especially true when playing a game on a large scale, I just don't want to do it alone.
Don't get me wrong, I will probably be among those who will give it a try on day one, just to see what the fuss is all about, maybe I'll like it, maybe I won't. I have a good feeling that Sean Murray knows what he is doing and many things have been added along the way. I'm sure they listened to the community and they added many features along the way.
So to your question..mmm.. you probably know the answer if you asked it. For anyone who don't know, here's Sean Murray answer to TapsMan who asked him that exact question: "..will it flop?" and Sean answered: