You think parents off-loading parenting to YouTube brainrot since 2014-2015 might have something to do with this? No, it must be SOCIAL MEDIA.
The modern trend is parents spending a lot more time and involvement with their kids then used to be the norm. The norm was that kid were outside unsupervised doing whatever. The expectation on parents went up rather then down.
Parents used to offload parenting to streets, fields and forests for decades. I don't think the offloading is the cause. But switching the offloading provider to SOCIAL MEDIA (of which Youtube is one) might've been.