There were many episodes where there were more than 6 people in I Love Lucy. I mentioned All in the Family because it was realistic and was showing people financially struggling even with two jobs. They lived in a house but it was small with one bathroom.
Even Seinfeld had a small apartment. Many other shows manage to show people living in small apartments. And even with rent control, it isn’t realistic at all.
So that is clearly not the real reason.
So writers are like “we will write a sitcom about this poor family of 10. Let’s give them a big house to fit them all”. That is ridiculous.
I won’t continue debating with you. I am amazed at how are you trying to justify everything about the show. Actually you are like the ones I saw on the fan sub on Reddit.