I am not even going to bother reading this article lol!!!
Points have been made already -- the study was about at-risk kids ONLY, and I love the comment that 'preschool is better than drunk Aunt Sally'. Sums it up perfectly. Preschool is better than some homes, but that does NOT mean that preschool provides a UNIVERSAL advantage.
Another point already made -- 40 years ago preschool was rare. We all turned out fine - we figured out how to stand in line SOMEHOW lol. I started school in kindergarten, and even then, when I hit grade 1 only maybe half the class had done kindergarten. For most, grade 1 was still the "first day of school". It's a VERY recent phenomenon for kids to go to school at age 3-5 as a "norm", and I don't think we've seen any overall improvement in kids behaviour or intelligence or respect for authority!!!
In fact, if you read some of Gatto's works about the real reasons for institutional schooling... you realize that the goals of obedience, following directions, standing in lines, etc etc, have NOTHING to do with the development of a well-rounded and healthy individual. It's about creating a subservient and obedient workforce that isn't too interested in challenging authority. But it's the folks who challenge authority who make positive changes!
Besides, if all you want is for your child to be a little better at following directions and you think a third-party teacher would have better luck than mom... well, first of all this can very much be a developmental thing, second it can be a parenting-style thing (unconditional parenting and positive parenting are a couple philosophies that come to mind that encourage -- not so much
obedience but
cooperation), and third, you don't need to go to SCHOOL to get that experience.
You can get that experience of being in a class with a teacher and 'group rules' by enrolling in a dance class, or a martial arts class, or an art class, or a gymnastics class, or a kindermusik class... all of which are only 1/2 hour or so each week, leaving the rest of their time to actually be free and be children.
Last fall, my daughter was 2.75yo. She wanted to take dance classes. We weren't sure if she was ready for it... the class was for 3-4yo (but since she would turn 3 before the end of the year, she could start), and she had NEVER done a class thing like this. In fact, she'd only rarely even ever had a babysitter. We could get a refund after the first month, so we decided to give it a try.
Well, we had no need to worry. After a couple of weeks of watching a lot (participating too, but sometimes just watching), and sometimes running around with another girl who started running around, she quickly got with the program. In fact, she loved to 'play dance class' at home, where SHE would be the teacher and she would boldly boss us around to stand in a straight line and not sit down when you're supposed to be dancing (I got a great kick out of being the 'bad kid' in her class, poor thing got awfully frustrated with my behaviour lol...)
There were other girls in the class, older girls who WERE IN PRESCHOOL, who did NOT fare so well. Who could not pay attention, who were running around, who were not listening and following instructions.
I honestly think that it's largely developmental. Some kids are ready for organized instruction (whether dance or math) at an earlier age, some not until later. Preschool does not TEACH these skills. The kids going to preschool either have them developmentally, or they don't. Then folks on the outside see the kids who are doing well in preschool and think "oh, preschool taught them that". Argh!! Completely ignoring 1) the kids who are NOT in preschool who have the same skills and 2) the kids who ARE in preschool and do NOT have those skills!
Anyway, I think if your main issue right now is defiance, to do some reading on alternative methods of dealing with it in order to elicit
cooperation. A large part of it IMO is modelling. We cooperate with her, she sees that, she's more willing to cooperate with us. She has her moments of defiance of course! And she is quite forcefully independent! But on the whole she is remarkably sensitive, empathic and helpful. Which she did not learn from preschool.

She cooperates because 1) she's interested in the activity we're doing or 2) she wants to be helpful for the sake of making other people happy. Not because she's "supposed" to be "obedient". And because 95% of the time we treat her with this kind of respect, the other 5% of the time when I'm in a hurry and I say "JUST DO IT PLEASE!!!" she's much more likely to say "oh, sorry mom, I'll do it"... unless she's having a tantrum of course lol... but that's a temporary thing which she will outgrow.
