That's true but the advantage with a generic device is that, same applications can be used by both normal and blind people with a (hope fully) little tweaking o

That's true but the advantage with a generic device is that, same applications can be used by both normal and blind people with a (hope fully) little tweaking on the app's part. For example, if it is a route finding app, a tweak to provide more frequent and detailed audio when set in disabled/blind mode will make it compatible for a larger user base. If they release some device only for the blind , then you will have to find developers who are willing to develop to a niche market.