The not-so-Great-Souled man...
<...Over 300,000,000 Buddhists in China believe in reincarnation, though a significantly less scientific form than the one I postulate.
So considering the massive population increase in the past centuries, where the heck did all the extra souls come from? As George Carlin once said, "somebody's printing up souls!"
This obviously lowers the value of the individual soul, and this "soul inflation" probably accounts for the reduced quality of the current crop of humanity. It's also probably why the Devil doesn't offer to buy the cheap things any more.