It may be Peggy, even more than Don, who is the ultimate example of the cost of upward mobility to which Matt Weiner alludes.

What we learned at the end of The Wheel is that Peggy may be willing to give up her own child in order to succeed in business without really trying. Isn’t that, finally, the nature of corporate life?

Peggy sees a world where people “want what they haven’t seen;” and she wants it to. She is being rewarded for intelligence and creativity in a way she never imagined, that is virtually unimaginable for a working-class woman in that era. And she wants that reward. She doesn’t understand it, she underestimates its financial value, she hasn’t seen it; but she wants it.

When Peggy arrived at Sterling Cooper, she just wanted to do well in a secretarial job. She didn’t understand what was expected of her, but she was determined to perform. I suspect that the sexuality was nothing more than performance; she slept with Pete, made a move for Don, only because it seemed like it was part of the job description. She had no desire for herself, only ambition.

But then Belle Jolie happened, and Peggy became a writer. She was celebrated. She was rewarded. And that was, finally, something she wanted for herself. As badly as Pete hurt her, success was way better than Pete.

So now that she has this thing she hasn’t seen, will she sacrifice it for love and motherhood? I don’t think so. I think that’s “Brooklyn” to her, and she’s set on her “Manhattan” path. Isn’t this exactly what Weiner meant by the cost of upward mobility? Isn’t this exactly the dark side of the American Dream?