Your "solution" to the problem that adults now are claiming to be unable to become parents is, literally, "cure aging".
Mine is "accept that you can not do it on your own and have them at a age where your parents can still help you."
The fact that people are forgetting these "old values" is what is bringing to this unsustainable state, and instead of accepting the reality of our limited lifespans and that people have managed to start having kids in the early 20's (or before that) for centuries just fine, you want to double down on the idea that "no one should have kids before their 50s"?