Some people do change. Some people do break their bad habits and pick up better ones. However, this requires an action plan, and more -- it requires taking responsibility for implementing that plan, one step at a time.
When Mitt is releasing tax returns to change the subject, you just know he's in a bad place politically. It may still be way too early to confidently predict the outcome of the election, but it isn't too early to call Romney's campaign (so far) an unmitigated disaster.