I don't know what has happened with Shanahan, but man how times have changed. My theory is that he is to much of an ego maniac and surrounds himself with Yes Men. He did it in Denver and now again in Washington. The talent got him over the hump in Denver, but he doesn't have as much in Washington and has a newbie QB versus on of the GOAT's finishing his career. That alone is a big difference.
That said, overcoming Snyder and the hole Washington was in before he got there is a tough spot, not to mention the salary cap restriction they have. Isn't going to get any easier next year though as they don't have their first round pick and have a big contract for Orakpo if they want to keep him.