Well, it’s not my sentiment, it’s the figure in the graph!

Right, but to make your point, you made the incredibly bold assumption that every minute is equally as valuable as every other minute. So because time with children = one TV episode of time, it can't be that important.

It's actually the opposite: If this time was so valuable, why wouldn't there be more of it? Why is it so important for the individual to have a child if you're never going to spend any time with them down the line? This is about what a specific culture (Modern Americans) are valuing. You can agree or disagree with that valuation (and whether it's ungrateful children or active seniors causing the time issue) but it's a valid analysis.

>Why is it so important for the individual to have a child if you're never going to spend any time with them down the line?

Why do anything in life at all? We're all going to die anyway!

> If this time was so valuable, why wouldn't there be more of it?

Money can be exchanged for goods and services

"it won't matter much" is your sentiment.

Presumably a parent of adult kids would retort that it's not just about the N hours of face to face, but also being proud of each milestone they hit (graduation, job, kids, etc), talking about the kids with their partner, and thinking about them.