One (or both?) of you is coming at this from the wrong angle. Faced with limitations, you have to find ways of living with them, working around them, and still living a fulfilling life.

That might mean you cannot travel the same way in retirement that you did in your 20's. That doesn't mean you still can't enjoy it, just that you need to take things slower and be gentler with your body.

Having/raising kids has been the most rewarding and challenging experience of my life. I cannot imagine how meaningless life would be to have all the money in the world and no kids.

I couldn't have said it better. It is an immense change for the better and for the worse, and it made us feel like that's when we truly became adults. It's one of those experiences that you can't understand until you go through it.

And I say this as somebody who really did not want the responsibility of raising children.

The other alternative is to find a fountain of youth very soon, or do you have another one?

I don’t think that there is any solution. It is what it is.

Then still better to channel desire to keep developing over to kids, no?

Good if it works for you, the reasoning doesn’t work for me, as I stated.