It's worth remembering, before attaching phrases such as "wildly successful": This is a game in early access, and with a very important legacy behind it.
What it has sold so far it has sold by virtue of its promises and by virtue of its legacy... NOT by virtue of actually being a good game. Do not mistake one for the other.
It may become the latter, but it isn't there yet, and it has a long, long road to travel before it gets close to that mark.
The second paragraph, I question. [/yodaspeak]
Do we know for a fact that it has sold even largely based on the virtue of its promises and legacy? (edit, here, I weigh the claim about legacy higher than promises, as I keep hearing about how it's not a bg game) If so, how? Because you seem to presume you can speak for around a million people (or at least a significant fraction)
I cannot speak for anyone else, but I bought it because I thought it would be a damn fun game from a great developer, and I have not been disappointed. Even now it's a good game in my opinion, and I think it has the makings of a great one.