I'm guessing cost and availability of care is a significant barrier. If you're a working class family, you might struggle to find qualified care that is actually capable of working with your special needs child's needs. Where maybe a retired family member can care for a more nuerotypical child, they may not be capable of adjusting to a special needs child's needs. Or if they're attending a commercial daycare, the daycare may simply be ill equiped and one bad day from saying "nope not worth it, we won't watch your kid anymore"

Many developmental disorders see significant improvement with early intervention with good care, but getting intervention this early can be prohibitively expensive (in my personal recent experience, $60 per appointment twice or more a week with decent insurance), especially before a diagnosis is achieved

Once the kids get older, especially if they're at a point where they continue to need individualized care they can simply be violent and unaware of the consequences for themselves and others. Unfortunately this is where the only support structures that exist in many cases are charities and prisons.

In my own experiences, I'm looking at moving closer to good care for my special needs child. Fortunately there are strong state programs and variants of Medicaid that I can lean on for financial assistance with everything a special needs child throws at us, being near good care could be lifechanging for him. But also, I'm lucky to be in the financial position where moving is actually an option. I have good enough insurance that we could persue diagnosis. I have good enough income and insurance to weather the very expensive care until Medicaid could kick in, and I have the flexibility to take off of work when needed to take him to care, and I just barely make enough that my wife doesn't have to work, so she can provide individualized care until he's old enough to attend school, as well as ferry him to his twice weekly appointments