To put that in context, when my grandparents were born, a typical family had around four children, and one in four children did not live to the age of five.
It is sort of crazy to think of what it would be like to grow up in that world.
I think a modern USA 1 year old has about a 99.97% chance of making it to adulthood. That means that if a modern USA adult loses a young child, there's a decent chance they don't know anybody who has had that experience.
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's not gone. It's just less common, and, at least in my experience, hidden inside churches where people are open about this sort of thing, and where, in a lot of them, miscarriages are treated as much the same thing, to be grieved over, as loss. Sometimes in private, but it's better when it's shared, because others have gone through the same thing, suffering silently.
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.
A few years ago I read of a pioneer woman in the Dakota region in the late 19th Century who had fifteen children, of whom 9 survived to adulthood. I can't begin to imagine the pain, and the fortitude needed to survive so much tragedy. As a parent, I can't think of anything worse than to lose one's child.
It is sort of crazy to think of what it would be like to grow up in that world.