I don't really see there ever being parity between the Air and Pro. There is parity between Mini and Air because the main differentiator that people want is screen size. That is not necessarily the case with the Pro. People want a bigger screen for the Pro, but also the hardware features that make it pro such as double the RAM, better CPU, more speakers, etc. People getting the Pro generally aren't doing it because they want a bigger screen size, whereas people buying a Mini are doing it generally because they want a smaller screen size.