If I had to guess, I think it's because they don't want developers optimizing for specific amounts of RAM and then having lousy performance on iPads with less R

If I had to guess, I think it's because they don't want developers optimizing for specific amounts of RAM and then having lousy performance on iPads with less RAM. If consumers don't have an easy way to find out which models have >X GB of RAM, then developers can't put it in their system requirements.