Parents and caregivers are beset with a dizzying amount of advice and expertise prclaiming itself the One True Path of parenting. Looking at bookstores and library shelves shows off more than a few authors and characters talking about all sorts of children.
It's possible that one of these experts, in the books, or outside of them, actually understands the child in question well and is able to provide useful advice, but it's much more likely that a caregiver will have to spend a lot of time, trial, and error with experts who don't work with their child before finding someone that actually does.
Things get more complicated because some of these experts proclaim they are right because they have advanced degrees and lots of experience in the field of child care, and others proclaim their expertise because they have no advanced degrees at all or experience, but what they did for their children worked, and is therefore universally applicable to all children.
Combine this with the time crunch that many parents are under and the fact that children don't age backwards, and finding a trusted expert that works in a short amount of time becomes a high-stress affair.