This is not a model. It's a 26-year-old mother with her nearly 4-year-old child who still breastfeeds as part of "attachment parenting." It is the latest issue of TIME Magazine.
I know a kid that was breastfed on occasion until 5 years old - I was shocked but 10 years later there is zero impact to the kid. So my views have changed.
Every child is unique, as is every parent. Good parenting is doing what feels right for each parent and child. I hate it when anyone outside that unique relationship passes judgement. Unless, of course, the child is being abused. Attachment parenting works for some, not for others. Just like pretty much anything in life.