Life’s greatest, least rewarding challenge; continuing to live when a loved one cannot.
It is sort of crazy to think of what it would be like to grow up in that world.
The ancient (and even, as you point out, very slightly pre-modern) world had a lot of "infrastructure" in place to deal with this, there were rituals and ceremonies and familiar people who knew what you were going through, and most of that is gone now.
It is indeed an enormous change.
But you're right, it's far harder to go through an experience alone, and loss of a child has certainly become far, far less common than it used to be. At least, if you limit it to the born.
In the US, in 2023, 1 in 3 never made it to birth.