It's amazing to see the low quality of the push-ups everywhere. People's spines (head and neck too) are draped along like the cables of the Golden Gate Bridge. And where are the elbows off to?
Is it from a lack of awareness, or are most of us just that frail?
This is the basics. Amp-up the P.E. and get kids doing these right. They have to learn to read don't they? Why can't they learn the proper way to move themselves (sad reality is it's actually re-learning how to move)? Maybe the teachers don't know how to do a push-up themselves... fine, LEARN.
I am not advocating drill sergeant basic training, but I am advocating a tiny bit of expectations.
There is a huge disconnect from the experience of "core strengthening" as an infant to the degression of adolescence, that just continues on into adulthood... Yes, our trunks are weak.
This is a fraction of the puzzle and a symptom of the bigger problem, but FIX THE DAMN PUSH-UPS FOLKS! ... and stop sitting in chairs so much.