I feel the discussion may be either:
Cheap enough or marketed enough.
Because never the article talk about it. So either it's cost prohibitive, our they couldn't even find it's existence. But again... If it were life changing...
Perhaps you missed this passage on a first read-through:
What would happen if we lost SfY? I have no idea. As I’ve explained
before, we have tried other communication apps and didn’t find any
that were a good match for Maya. Interestingly, we also carefully
considered purchasing a communication device from PRC, and met with
one of their representatives in November, nine weeks before a post
on my Facebook wall introduced me to SfY (and seven weeks before it
even existed in the iTunes store). We examined PRC’s devices and
were disappointed to see that they weren’t a good fit for Maya.
For us, this wasn’t an issue of an expensive device versus a
“cheap” app. This was an issue of an ineffective device (for Maya)
versus an app that she understood and embraced immediately. The
only app, the only system, that she immediately adopted as her own
way of communicating.
Because never the article talk about it. So either it's cost prohibitive, our they couldn't even find it's existence. But again... If it were life changing...