Your source only includes married couples with children, not Americans in general. There's many variables that changed to fulfil that definition in the meantime.
For example, these days said couples tend to be older, more educated and with less kids on average. Which may explain why they're more likely to be dual income. You don't have time for a second job when you have 5 kids to raise. But that's less likely to happen today, statistically speaking.
So your comparison most likely compares people in different stages of life, not the same people across generations.
But in any case, the worker participation rate has stayed between 58% to 68% over the last 70 years, with around 63% today. Doesn't sounds that big of a difference to me.
For example, these days said couples tend to be older, more educated and with less kids on average. Which may explain why they're more likely to be dual income. You don't have time for a second job when you have 5 kids to raise. But that's less likely to happen today, statistically speaking.
So your comparison most likely compares people in different stages of life, not the same people across generations.
But in any case, the worker participation rate has stayed between 58% to 68% over the last 70 years, with around 63% today. Doesn't sounds that big of a difference to me.