As howtheduck reminds us, John's allowing Elly to work for the week is simply a means by which he can discourage her from working outside the home. Given that he's deprived her of the chance to learn how to hunt for jobs like other people, not bothered discussing salary and hopes that showing her what the working world is like will scare her back into the motherhood that's supposed to content her. Given that she really is a self-absorbed, narcissistic poser who only wants to do this to make a big production out of it, his scheme works. Her next craze is trying to pretend that the only degree she wants isn't the MRS. He doesn't even have to do anything to stop that because of her low boredom threshhold. What he does have to do is stop her whining about his impulse purchases; cynically (and correctly) judging that when he buys nice stuff for himself, she wants nice stuff too, he hit on the scheme of sweetening the pot by more or less bribing her into compliance with his buying ego-gratifying toys and train houses.