I don't expect Pentax to go after the 100mp 53.4x40mm chips, 44x33mm is more than enough, especially with a refresh from Sony to be had soon. The DA 25mm was dropped not too far back, and some folks think it was due to the image circle it could support.
GFX & X1D are tied to the 44x33 chip size, so when Sony releases a higher MP chip, it'll make it's way to these cameras, though I wager it'll be after the full size backs get a refresh and they get the sensors happier without as much cooling tech required.