I debunk this.

The requirement for multiple screen readers is a simptim of a broken accessibility system poorly implemented.  Name one other platform where multiple screen readers and switching on the fly are required for reliable access?

The problem with windows was is and probably shall ever be that it doesn't comply with it's own standards and relies on third parties to hack access into existence.  Since no one can keep up with everything, some things will invariably work differently across the board.  Then add stability issues caused by the veritable hackathon, video card instability, third party scripting issues, and (in the case of one product) outright denial of service caused by it's own draconian content protection scheme, and you get a quagmire.

I don't know about linux so much, but mac, Iphone, and android for sure are all really slick accessibility products where the expectation is that things will be stable and accessible out of the box as a baseline.  If a product or feature on those platforms is not accessible, we bring the quality of development of that product or service up to meet the standard.  On windows, we bring the accessibility tools down so that they can crunch through the mess and come up with something that works as long as there's time, money, demand, and co-operation from the vendor of the product.  It's bass ackwards, and we've more or less tollerated it because it's what we are used to.

Best,

Erik