Cautious that I don't really want to add to the various armchair theories here but this is one I am not actually aware of any research on and since people have talked about various aspects relating to this. (If anyone does know I would be interested to see it).
A few posters have mentioned this category of children with (presumably autism?) who are non-verbal and have large amounts of disruptive behaviours, as being a growing category or one which seems more represented today than in the past.
Could it be we are seeing this because this is what chronic stress looks like in autistic people?
(Which is two questions: Is it likely that autistic stress manifests in this way? In my understanding it is, but I am cautious that I am not that knowledgeable about autism; and is it likely this is what's happening in this case?)
If you are working with this group do they tend to improve once given proper support (or does that support not really exist, because you can't "support away" modern life?) I feel like there is a perception that there is a specific "non verbal and violent" type of autism vs a "quirky and sensitive" type of autism (aka the old Kanner vs Asperger argument) but these are stress responses, aren't they? And I have definitely seen threads and resources explaining that the delineation of autism into "types" is unhelpful specifically because autistic people can move between different levels of functioning based on their stress levels and the environment around them, throughout their lifespan. And that some developmental delays in autistic individuals could even be caused by this type of stress, not directly, but because if you are under the amount of stress that causes you to literally shut down, then how do you even start picking up social skills, or toilet learning, or speech development, or access skills you previously used? And we know that once someone falls a little bit behind it can be difficult to catch up because there is a feedback loop where they have inadequate skills so accessing the activity or interaction is frustrating or aversive so they avoid it which leads to even less skill practice.
I feel like this would fit in with the idea that modern life is so much more overstimulating, fast-paced, everyone has to fit into a box where we are all the same (though I find this a bit confusing because I always thought that was more what it was like in the past), families have to be two-income and grandparents work to older ages or are already infirm when their grandchildren are born, so children are in outside care longer and younger, there is a lot more commuting in cars rather than walking everywhere, curriculum/homework in infant school rather than a slower pace and more flexible classrooms.
So the theory being that autistic children with this high level of needs might have always been there but in a different environment their stress level would not be so great, so their level of need might not have been so great.