How many units does Xbox One need to sell to be considered a success?

[nanarchy]

Mr Puggsly said:

So I think we can all agree X1 is a disaster like no other and MS has no business in the home console arena. Maybe? Maybe not?

So VG Chartz has it at 28 million, but how many does it need to sell to be worthwhile endeavor?

I think about the only thing we can agree on is that that is troll bullshit. X1 is already a success, certainly not to the levels they would have liked but it is definitely pretty good, especially considering the disasterous ps3 type start.