I think Carlsen understood from an early age that ratings follow performance, not the other way around
I agree. But that doesn't mean he wasn't concerned about his rating. He just had the skill set and ability to do something about it that few others could do.
To reach 2000, I recommend you read Chess Fundamentals by Capablanca (my favorite book for beginners), and then read My System by Nimzowitch. By the time you are done with those two you will probably be very close.