Much of the US housing stock includes homes built before 1990 (30 years ago). If most of the median home price increase was due to build quality there would be a bimodal distribution of housing appreciation with newer homes having appreciated more than older homes.
Most of the appreciation in housing is due to higher household incomes due to two income households.
I would change your last sentence to: is due to higher household incomes due to two income households without a similar increase in the supply of housing near where jobs are.
Why bimodal? Houses are being built every year. So maybe houses built in 2023 have appreciated 1% more than in 2022, and those have appreciated 1% more than 2021, and so on, leading to a smooth distribution.
Most of the appreciation in housing is due to higher household incomes due to two income households.