If you'll notice the Georgia State study referenced in the article, I'll bet that is the reason a lot of middle class families enroll their children - and I bet it's one reason the program seems to exascerbate the achievement gap.
I haven't read the study, but I'd be willing to bet that while the lower-level children improve, those at the top improve more.
You’re probably exactly right. I did make the mistake of putting my oldest child in the public school kindergarten (it has a wonderful reputation, of which I personally would beg to differ!), and because most of her classmates had been through the pre-k program, most of the children were able to read beginner books very early in the year. By halfway through, they were required to take turns (2 kids per day) to read entire books aloud to the rest of the class, and by the end of the year, they had written, illustrated, and bound story books of their own. It was a far cry from the coloring and learning letters and numbers that we had at the same age. Luckily, even though my daughter hadn’t been to “pre-k”, I had “played school” with her at home, complete with and old school desk, and she already knew how to read, spell, and do elementary math before K.
The sad part of the K program was that the children were pushed so hard to work and excel, that they didn’t have any time left for just being kids. Just like in the rest of elementary school, they weren’t allowed to talk to each other except at lunch (and then only to the person on either side of them, quietly) and at recess, which was 15 minutes, and at “centers time” (where they had their choice of a location to go to in the classroom, which could be computer time, reading time, coloring time, etc., where, again, they could speak quietly to the child(ren) right next to them). The rest of the day, they sat in a chair at at a table and did schoolwork. Our daughter’s “energizer bunny” personality didn’t mesh well with all the physical restriction, so we have been homeschooling her ever since (she is entering 8th grade in the fall, and still takes a break to jump on her trampoline or ride her scooter for 10 minutes after every 45 minutes or so of work!).