Same thing happened to me, I slacked off on preordering it so I placed a late order for one on each platform. It may not have a big production run and may be harder to find later.
Also don't forget about Raiden V, not widely available for preorder and still includes the Prime discount. Amazon said they wouldn't be offering Prime discount for collector's editions in the future, but this is a cheaper CE so probably not included in that:
Yeah, the discount will likely stay though if they take it away I believe Bull Moose has this listed for $35.97 and no tax (for most), which is almost as good as the Prime discount.