One of the points of a PP is that they fill the tank with more water than a traditional RO. A PP hides the back pressure of the tank from the membrane. Membranes need a differential pressure to operate properly. Thus the use of either no ASV or a 90% ASV. You can use a 60% ASV with a PP but you lose one of its enhancements. WOW overcomes some of these issues but the complexity, proprietary design, and other problems are simply not worth the tiny advantage that you can get with WOW.
A PP has no limit on tank size or number of tanks. I have even been successful using the ERP1000 with up to 500 GPD membranes (other than the noise). We use these with 119 Gallon RO tanka all the time for many light commercial applications. WOW can only do this by adding more systems. I am sure someone can develop a larger system but the cost would be too high considering the very limited market and the unnecessary complexity that a simple PP can work almost as well.
A 60% ASV is used on traditional systems since it keeps an adequate differential pressure across the membrane, but as the tank pressure builds, the production rate goes down thus the efficiency decreases since the waste stream stays the same.
All that being said, 25 years ago a lot of this mattered since the technology was complex and expensive. Now a high end RO is can be had for about $500, a Piece of garbage RO is about $100