5 year olds "know amazing wealth of knowledge about the world and how it works"?? Que? How many 5 year olds do you know or interact with?

Your statement is exactly the incarnation of Moravec's paradox. You don't see the amazing things that a 5yr old (even a 2yr old) can do, exactly because these things are completely obvious to us. They become much less obvious once you want your robot to be able to do these same things. At that point these things become horribly difficult.

You're severely underestimating children (or over-estimating the current state of AI). 5 year-olds have better natural language skills than any AI in existence, better motor and navigation skills than the most advanced DARPA robot, better mood recognition capabilities, etc.

You appear to be thinking of just facts and figures. AI is not that.

When did I mention AI?

How many robots have you interacted with?

5-year old humans have picked up a lot. For instance, I knew about the dangers that hot surfaces, sharp objects, angry cats, and big sisters represented.

I had learned to walk, run, swim, ride a bicycle, and catch a ball.