They are planning a hail-mary pass by opening their own office in California. Their reasoning is if they are making money, the McCann crowd has to let them be.
That is probably on the money. But the reality is that most of them are has-beens. Don's best creative days are behind him. Most of his focus is on fantasies about what could work. He sees California as sort of a Promised Land. There, seems to go his magical thinking, is where he will conjure up his creative powers.
Peggy has to also make the shift to career-path thinking and out of the past. A headhunter tells her to stay with McCann a few years, then make the big move. She doesn't make to do that. But she may have to.
In addition, the ghosts of the past come to haunt her as she has to select a child actor for an advertisement. The boy she gave away would be nine years old. Like Don, she has broken pieces which she hasn't addressed.
What hovers over this episode is that the past is over. The characters won't have a future unless they can let go of that past. The odds are that they simply aren't emotionally equipped to do that. Unlike Jimmy on "Better Call Saul," they seem incapable of change.