I would argue that ROI is extremely important in education. It's just that the "return" on our investment is not purely financial. Producing students who will be competent to effectively participate in and wisely run the society of tomorrow is a large part of the return that we seek. So, to that extent it may be that high special needs costs are worth it if they demonstrably help students become self-sufficient instead of dependent wards of the state. I can't say for sure that they are worth it, I'm saying that the mere fact that they're expensive doesn't mean they aren't cost-effective in the greater sense.

Those are still returns, just not monetary ones. You can get plenty of buy in that educational outcomes are good in themselves, but schools fail at that basic metric.

On the other hand, as a way to provide social services to underprivileged children they are pretty decent. But that's not what they're advertised as (school isn't known as an acronym for Social Care and Health Out Of a Location), and people end up pissed.

Are you saying "whatever it costs, it doesn't matter"? Because I can't agree with that. Nor is it good public policy to just be "not assholes."

The absolute dollar amount does matter, and it has nothing to do with being assholes or not. There are different ways to meet children's needs and spending an infinite amount of money is just not sustainable.