You're pointing out the effect of everyone working full-time. I told you what needs to happen if we want a society where women can work outside the home and there's no fertility crisis.
And what I’m saying is if you want a high birth rate you have to have a culture where women don’t work outside the home and are not empowered which is what the data shows. What you’re suggesting is hopeful conjecture that has many, many counterexamples in today’s world.
There's counterexamples of countries where enforced 50% time schedules for couples are the norm? I haven't seen any myself...it's about as realistic as "force women back into the kitchen". But much fairer.
I would love to see an example of a country where couples with children can each work 50% time but get paid like both are working full-time. Unrealistic, yes. But also arguably fair.