>>10176669It was released late October, I think. Based on reviews that were on the item page, some people had gotten it in hand and there was at least one video review for it.
https://www.youtube.com/watch?v=GrDkRoi-QmgLooking into it a little more, apparently this has happened with other Amazon exclusives in the past and sometimes the page goes back up when they restock. Even if it doesn't it's not a huge loss, since they'll all eventually be released individually, though the total cost ends up being more than the 4 pack.
It's hard to estimate the sales, though it seems to be doing better than the other Avatar lines, especially McFarlane's 7" line which I see frequently discounted and rarely hear about.