These who are able to have healthy offspring late in their lives are at tremendous evolutionary advantage now, whereas historically it was a selectionary 'meh'.

I wonder if that leads society to unwittingly be selecting for longer lifespan, if maximum lifespan and maximum reproductive age are correlated.

Lifespan is almost worthless if you are not in tolerable mental and physical condition, and prolonged fertility likely correlates with both. You need to be fit to be fertile.