TL;DR McCarthy took the job for the bucks. He was burned out his last couple of years at Green Bay, but he'll take $4 million to say "sounds good boss" whenever Jerry has a random neural firing.
Confession: I haven't watched a Cowboys game since Garrett iced his own kicker. That was in 2011. So, you know how up to date I am on the team.
The soliloquy: Jerry's early success hurt him later, and (IMHO) he's a functioning alcoholic. His decisions remind me of playing poker with a drunk. Ever play poker with a drunk, he's sitting on two pair, and still throws money on the table like it's four of a kind?
The Deion Sanders trade was what ruined him. He traded for Deion, they won the Super Bowl next year. It set two patterns. Jerry became convinced he could identify talent, and he also thinks he's perpetually one big signing away from a Super Bowl win. He picks a guy, figures HE'S THE GUY, and that's how you end up with the Elliot contact, drafting a fourth rounder, Quincy Carter, in the second round, and filling out the roster with a bunch of guys named Norm.
Tom Brady turned the Patriots, and then the Buccaneers, into places people wanted to go to win. Jerry turned the Cowboys into a place where guys want to go for a paycheck.