One of our clinicians stated this at our last Internship/Residency meeting, "You don't specialize because you think its cool to be a surgeon or because you like the way all of the extra letters after your name look; you specialize because its something you HAVE to do. Something you can't imagine not doing."
I think he hit it on the mark. After spending years to get the prereq's and years in the DVM program most people just want to get out in the real world and make some money for a change. (And yes interns/residents get paid, but not much.) If its a field you love AND want to spend the rest of your life working in a career that uses those credentials, then you specialize.