Goq, I don’t think it’s fair to generalize. First of all, those tragedies that you mention are just as prevalent among secular people who don’t have large families. Every summer, there are PSA’s about kids in cars and water safety etc. These things can r’l happen to ANY family, large, small, black, white, educated, any religion or none at all (there was a famous article in the Washington Post about parents who left their kids in cars, and it’s humbling to realize that yes, IT COULD BE YOU).
I do believe that having children needs to be thought through, and just because yenem has 12 doesn’t mean you should too. Children are a tremendous bracha, but it’s also the hardest thing you’ll ever do in life. Although a competent halachik authority must be consulted in these matters, the fact is that family planning is NOT assur. You can have a large family and still be smart about it, taking into account the needs of your particular family. But to insinuate that any particular number of children is “too much” is insulting. I know many double-digit families that are doing an amazing job, and I know some families in total chaos and dysfunction with just 1 or 2. It mostly has to do with the parents and family dynamics- family size is just a number.