The story of a marriage was an excellent way to fulfill the goal of discussing class without discussing class, and to tell an audience that they were upwardly mobile.
Movies with interfering in-laws and kids are often presented as comic, the ridicule bringing welcome relief to beleaguered married folks suffering offscreen at the hands of relatives.
Everyone will tell you how rigid I am, but a teacher has to be flexible. You can't cut the student to your cloth you have to cut yourself to theirs.
Another superb movie about a mature marriage grounded in a fundamental lack of communication is Dodsworth, based on the Sinclair Lewis novel.