Well, I think in the context of the parent comment, separating out housing would risk overstating changes in its effect on purchasing power because increases to housing would already be captured by inflation (since we're talking about real median income, which is already inflation adjusted)

I agree that housing affordability is a major problem and that looking at it independently could help you quantify if housing specifically has become more unaffordable, but that's a different question then whether the median person's overall purchasing power has declined (considering all of housing, healthcare food etc)