My own family background is a farm. I remember my little sister worrying who was going to take it over "because one of us has got to" when she was about nine, and ours has only been in the family since 1920 rather than before Alfred.

Rowan is more confident and competent than Karen and Karen resents Rowan being better at dealing with fusses than she is but Rowan isn't academic and taking over the farm and leaving school is a way of not having to compete with Karen on that score. After which it must be particularly infuriating to have Karen chuck Oxford and turn up doing her own self-sacrificing step-mother bit on the doorstep.