First, the ending was incredibly economical. Think about how much information was communicated in those final few seconds. The obvious implication is Don creates the famous Coke commercial for McCann. But that also means Don goes back to New York. Back to the agency. Back to Betty. Back to his kids.
Efficiency isn’t typically the hallmark of great art, but in this case, it was crucial. As a friend of mine pointed out, Weiner could have shown us all that. But it would have taken a lengthy parade of maudlin and melodramatic scenes. The kind of stuff we’ve already seen so many times before, not just on Mad Men but elsewhere.
Second, the ending crystallized the themes of the show perfectly. There were lots of hints in these final episodes that you can’t go back. One of the clearest was Don’s attempt to “fix” Stephanie’s problems. Ironically, even his speech about “going forward” was a throwback to the past when he delivered a similar speech to Peggy. Classic Don Draper.
That Don died at Esalen and was reborn. The old Don would never have spontaneously hugged that crying man in the workshop. Old Don wouldn’t have done meditation in the morning sun -- at least, not voluntarily. And he probably wouldn’t have come up with a commercial that captured the changing times so perfectly.
In the end, Don didn’t just go back, he went back a changed man. And that change makes all the difference.