From TFA: 'the ability to wake up and say, “I can do whatever I want today.”'
Hard to wake up and do whatever you want if you're paralyzed/in a coma/cripplingly depressed.
I don't feel I have much choice at all on what to do on a given day—or any single day of the year for that matter.
If you could keep the kids and everything you had, but also have even more freedom to do whatever you want (for yourself or your family - more vacations and play time, more opportunities for education and life experiences) wouldn't you feel even wealthier?
If you had less freedom (stuck working long hours, can't choose a family doctor you trust, etc), wouldn't you feel less wealthy?
Importantly, you don't have to act on the freedom to know that you have it.
Sometimes, people want to (or need to) make choices about what they want to do for the next 10 years. Having children is a choice like that (except that it's for even longer).
Making such a choice undeniably restricts your ability to revise your choices on a daily basis, but can also represent movement towards a longer term goal that might (or might not) ultimately bring even more happiness.