When I inquired about this, I believe I was told that the reason we don't see one is because Callaway does not make a 64 deg wedge and the "clubs" available on WGT simulate what is also available in the real world.
However, a search on the web will show that Callaway does appear to offer a 64 deg wedge in various models in at least 2 forms... the Mack Daddy PM grind and the Mack Daddy 4 Platinum.
I guess it is possible for them to eventually make this available but it appears they are putting more effort into making sure mobile users can change the color of the sponsor apparel rather than potential "matching clubs" for users.
Now, before that is taken as being overly critical, we did see a release of new Titleist Clubs for entry level players. So, I am holding out a little hope that they will consider releasing some Vokey Wedges or the "missing" Mack Daddy in the realm of a 64 deg to complement the existing line in the higher levels but it is really hard to say.
The 64 deg is far more marketable and applicable to this game than the 52 deg wedge that plays to 115y which I believe is likely only purchased as a mistake by some not realizing how redundant it becomes by overlapping so closely with the PW in most iron sets in the game. As such the 52 deg appears to be a wasted offering and I don't know of anyone that plays it but I could be wrong. I have seen a one or two players on WGT that carry 4 wedges but that is very rare!
updated (I was wrong about the 52 deg to an extent) there are a couple players Peter in particular (Ujjbnjk) that plays the 52 deg wedge and would swear by it... given his proficiency in the game... I have to admit it isn't a complete waste like I first thought.