I beat that drum in May of 2017 and again in July 2018 and have even commented on it further since then.
I have pointed out Phil Mickelson for whom the line is named after and helped design/ create the new wedge would likely never be caught playing without a 64 deg wedge and has been known to carry up to 4 wedges at a time even opting for something more akin to a spoon that was something like a 68 or 70 deg for one tournament if I remember right.
When a 64 deg did not come out with the new PM Grind wedges, I pretty much figured we have our answer - we are very unlikely to see a another high end 64 deg wedge introduced to the game.