We Should Be Having More Kids
youngmoney.co
youngmoney.co
First up, there's mention of average childcare cost per year, and then contrasts that with median income ("half the population"). Also, it's more important to know how it compares to figures in the past: what was child care cost and median salary "back in the day"?
Next, while there is a certain shift to childbearing years coming later, it's not trivial to estimate the actual children-per-woman without waiting out for that shift to "complete" (and it might actually rebound, mostly as us older parents realise how silly we were to wait out that long, with all the physical ails and pains we now face in our 40s chasing toddlers and kids around). Basically, if there was a sudden shift where everyone decided not to have kids before 35 after they used to have them at 25, there'd be a 10 year window where birth rates would be significantly lower and they might rebound right after (say, there was tax provision which made it hugely beneficial to do so). Unfortunately, the shift is not sudden but gradual which makes any estimations harder (though not impossible, but nobody does take that into account).
Finally, retirement calculations can be made to accommodate populace getting older, and offering transparent retirement options to current earners (pay this much to retire at this age with this big of a pension). Basically, as you note, the math is not too favourable, but if it provides upfront options (eg. pay 80% of your income for early retirement, but at least 50K yearly), it will both encourage and discourage people from doing so.
And it also neglects the fact that there are many people who like doing useful stuff, including outside their jobs. Us reducing dependence on job having should be the goal, but we are still early in trying to figure out how that works on large and global scale.