Those “no birth planning whatsoever” kind of people make the Catholic Church look downright moderate on the issue. I think whether it’s ok or not to have child after child lies in the conscience of each mother. If the mother knows she is not giving enough attention to the chidren, or is neglecting her husband, then it is probably wrong of her to keep having them. But if she knows in her heart she is providing well for the children in every way, then I see no problem with it.
I know many people who don’t have time for their 2 children, shipping them off to daycare for 50 hours/wk– it would be scary if those people started having a baby every year.