I recall a talk where the speaker (I think Elizabeth Warren?) argued the opposite; when the budget was doable with a single job, then when the primary breadwin

I recall a talk where the speaker (I think Elizabeth Warren?) argued the opposite; when the budget was doable with a single job, then when the primary breadwinner lost their job, both adults could get lesser jobs to make a large fraction of the previous amount and give a longer runway. However when you are already relying on both adult's salaries just to service debt and pay rent/mortgage, then you are more fragile. I can see either one being potentially true depending on circumstances.