I am starting to believe that the DAW being beta tested will be the successor to P5.
The cynical side of me says that they must have a reason to stop selling P5 altogether. Even if P5 did not sell much, the cost of having a few pages on their store site dedicated to P5 was probably less than what they might have generated in sales. If P5 sales cut into sales of the new DAW, then obviously it would have to go.
The optimistic side of me thinks that perhaps P5 is going to be replaced with something similar, but more advanced. With a catchier name.