Now, when you send your kid to kindergarten, is it the teacher's responsibility to potty train them or are the kids already supposed to be potty trained so they can concentrate on other stuff.
Funny you mention this, as my kiddo has multiple classmates in Kindergarten that aren't potty trained, don't know their letters/numbers, can't write their name, don't know their parent's names, etc. Parents anymore expect teachers to raise their kids in addition to teach them, and that just doesn't work.
And first grade is even worse, as there's no 'mandatory' kindergarten in some states. Imagine a kid walking into first grade that doesn't know the above things, still craps their pants, and the parents tell the teacher 'he's your problem'. This is what teachers deal with now...but I digress.
---
Going back to football, Fox Sports SW had a piece a year or two ago about how inexperienced and improperly trained peewee football coaches aren't teaching kids proper tackling techniques for years, and it's manifesting itself in the high school and college ranks, as kids have to be 'retrained' to tackle properly and still revert back to what they learned initially when they're not paying attention.
Not saying that's an excuse for everyone...but when you've been trained early on to do something a certain way, it's hard to break it.