Play based learning

Play based learning has begun to trend and in my usual fashion, I am doubtful. When teachers are responsive to children, there will be an expectation that play is part of learning. However, unless there is a strong understanding of the different processes of learning and strong understanding of the curriculum, play based learning doesn't allow for the important stuff of scientists and artists and historians etc! 
I don't think children play science, art, history etc, they do it and do it very well.