This is a brilliant analysis! I would imagine the AB side of it is a more intense need of security; or simply the feeling or relief from stresses of real life. Lawyers, high rank army men, corperate managers, and high responsibility job positions often contain ABs. Its the switch from having huge weight on your shoulders to being looked after with no responsibilities to worry about.
There is one thing that confuses me about fellow DLs. Where does the sexual attraction come from?!