Regardless of how you slice it... an extended family household has multiple adults. That means the US leads the world in children being raised with only one adult around.

EDIT: Also, to be clear, an extended family household means that mom and dad could still be around, so it says nothing of a household with only either mom or dad (most likely mom, according to the article).

I can't see why single parent has a bridge to extended family. Single Parenthood is about parents splitting, extended family is about mutually supporting generations.

Anecdotally, I know quite a few extended family situations, but only one single parent. Non-US context.

Anecdotally, non-US, many of my friends grew up in these situations (single parent, extended family helps take care)

I have seen this in the US, but my sample size is very small even for an individual.

It might not even be detected on surveys. The parent would say they were a single parent if asked, which is true, but family pitches in a ton.