What's all the hubub?
All the 1st vs 3rd comparisons are rubbish. And the baby kilns? Seriously?
This is about as low hanging fruit as you can get. People in industrial countries for the most part have ready access to cheap, effective birth control methods. They can use them or not, their choice.
People in third world countries, not so much. Expensive relative to incomes and in many places difficult to impossible to obtain.
People like having sex, raising babies not so much. Why not make birth control available to anyone that wants to use it? Is the world so devoid of people that we need people raising more babies if they aren't interested in having them?
Lots of old people is a short term problem, but pumping out even more soon to be old people is just kicking the can down the road. No that's not right, it's kicking the can down the road and welding on bits as we go so it gets even bigger. Just as you can't spend your way out of debt, you can't boost population forever to take care of previous population booms that are not aged, it just delays the day of reckoning while making it even worse.
And this may be an unkind thing to say, but keep in mind that no matter how bad the ratio is between youngins and oldins, the problem can't last longer than a single generation (unless we kick the can down the road).
Maybe we are doomed to failure, if even a no brainer like letting people who don't want kids have access to birth control is shot down out of hand.