This seems correct to me, I've watched my niece since she was two (she's 4 now) navigating YouTube on her mom's phone or tablet. She watches mostly kids playing with toys and the adults in costume nonsense videos mentioned below. All the vids she watches are made for YouTube (e.g. not casual one time uploads) and everything I've seen her watch has over a million views. YouTube's recommend feature let's her bounce from video to video endlessly. Also this easily allows for copycats. There a ton of channels that do the adults in costume nonsense videos now and they all have huge amounts of traffic.