The issue I have with the base model Mac's being under-memoried is that the base models are the high volume models that have sales and are easier to get at vend

The issue I have with the base model Mac's being under-memoried is that the base models are the high volume models that have sales and are easier to get at vendors other than the Apple Store. iPhone's have been under memoried at significant periods during their life, but most stores carried an upgraded model. I find the non base model Mac's often aren't available at launch, have longer lead times and force you to go to the Apple Store where you won't get any discount of any kind and often find a longer lead time even there.