In my experience, a lot of parents don't want their children to outgrow their babyhood. I haven't seen lots of the other things mentioned in the OP, unless there was a real need. One place I have noticed it is with potty training. Some parents are happy to wait until their child is more on the side of 3 yo and gets it, then pretty much accomplishes it in a weekend, whereas other parents train for a year or much more then finish at about the same age.
And I do think parents change their ways of doing things as each child arrives in the family. How many, with multiple children, made a nice elaborate baby book or took tons of pictures, with their first but then less with their 2nd, and very few with their 3rd and more?? A bigger family means less time, less energy, less fight.
And we learn along the way too, we change our parenting styles. At least I did.
My kids never let me forget it either. Especially from their teen years. 'Why did you let L do that but you never let me do it?'