That beautiful young age is great, BUT.... far more families have TWO working parents that are not home to care for their kids. Few people live in extended families, with a Grandparent, or other relative, home to help raising the kids. Many families and single parents rely on daycare to take care of their kids and hopefully to teach them some manners, some ethics, some 3 R's, etcetera. Many daycares are a just a place for kids to run amok and sit in front of the TV. Not exactly a good way to learn as more studies prove all the time.
We were fortunate that our kids experienced daycare providers that put time and effort into fun, education, morals and ethics, and quality meals and hygiene. I see some other kids missing out on that- both at home and in daycares. It's unfortunate.
I think the availability of all day kindergarten takes the stress off of parents that are already pressed for time, money, help with bringing their kids up to be "good". In a Gomer Pyle or Beaver Cleaver world we would all have two parent families; one parent would bring home the bacon; Dad would play catch with Jr. after working a 9-5 job; Mom would always have dinner ready at 6:00 PM where the family would eat together; the kids would be "A" students; and there would be a nice house with a dog in the back yard for all; and they would all have a new car in the driveway.
I for one am glad to see all day kindergarten as a means to help families.