Early childhood development experts maintain that preschools should be caring, stimulating, child-centered environments dedicated to the overall social and emotional growth of young children. Teaching reading to preschool kids isn't on their or my developmental priorities list, especially since all kids are hard-wired on an individualized basis to learn something as complex as reading.
Teachers and parents have created a demand for kindergartens to teach what first grades used to do and for preschools to become kindergartens. I deplore this shift. Read David Elkind's classic, The Hurried Child for an expanded, brilliant exploration of the unnatural "speeding up" of childhood.