You make two obvious errors in your article. The first is that schools are not a public good. “Public good” is a term often abused by socialists (and I’m sure others who don’t understand the meaning) when it actually has a specific meaning in economics (a non-excludable, non-contestable good).
Schools are in fact a common good (or common pool resource), which is a good that is non-excludable but is contestable. How you deal with common pool resources, economically, is very different to public goods (and we shall see below).
The second mistake you make is to take the case of a specialist need, like disability, and generalise it across the whole structure of supply. In the UK, where I live, the healthcare system has also made this same mistake. Every district general hospital (DGH) has to supply every service (as if this were axiomatic) — no matter how specialist or sub-specialist the service is.
This is a classic case of how local politics and socialism misallocate resource. Not every DGH can possibly provide a quality service for hyperacute stroke care for example, because you need very high quality and resource intensive ICU and ER facilities to do so, as well as sub-specialist doctors. There just isn’t enough money or resource to go around, and the price is lowering of quality for all patients.
It would of course be better to move to a model where a few specialist larger hospitals provided this care. While this would mean a slightly longer journey for some, the overall quality would hugely improve. But because in the mindset of socialists healthcare in a public good, rather than a common good, the idea of rationalising the structure of supply for specialisms is anathema. If healthcare is truly public and therefore non-contestable, isn’t it reasonable to assume every hospital should have a stroke unit? The result is substandard care for all — bringing everyone’s level down rather than raising the level for most.
And this, after all, is the fundamental body politic of the left. It’s better to have bad services for all than good services for most, and less good for some special cases (even if less good just means having to travel further). Socialism is the art of lowering standards, income and conditions for everyone in the name of “fairness” — because equality of outcome is more important than quality of outcome.