Without turning this into a debate over The virtues of SAHP and nursery etc etc the governments overriding policy is to encourage both parents to work and the cost of living makes this a necessity in many families.
Many children are put into childcare situations v young and they are obliged to follow the EYFS curriculum. As a SAHM I have noticed a real difference in the development of the children at nursery because they, even at a young age are taught in a more structured way. Even if they delay starting school - lots of children will just be in structured childcare settings anyway. Most children really enjoy it too my ds has just started Pre school and he loves it.
Of course Gove is going to dismiss this research, if he agreed with it then it would contradict the governments policy of encouraging parents back to work using child care.
Whether the curriculum should be changed that's another matter.