PM take longer to crop, set less fruit and need pollination a lot of the time. They are also a BIG tree. Not great for an uncommitted farmer or market.
AP was for a long time the easier of the atemoya to grow. Interestingly, farmers now complain about the Paxtons Prolific (KJ Pinks) because the thinning of self set fruits takes longer than pollination would take on the original mammoth.
There are a number of reasons why it would not be the variety of choice for industry, but not really based on quality.
As background, it was a selection made here in Brisbane (Bowen Hills) from seeds sent from Guyana of an unusually large fruited tree there.