This is an interesting topic.
The embedded link isn't paywalled and is somewhat more complete as it also addresses some of the marriage benefits tax-wise such as selling an appreciated house.
https://wustllawreview.org/2022/08/1...n-later-years/
It seems to me that there was a tendency to write some parts of the code to "even out" the situation where there's a large difference between the incomes of the married pair such as the case of the stay-at-home mom.
If/when a moderator sees this thread, it might be deleted due to copying the entire article.
It could be restared with the above link, but better done in the Economics forum which has a more advanced-knowledge population.