Garry, it's good to see you helping where you can. You're absolutely right, it's not easy as it should be. Very young industry still. Computers were quite complicated to use in the early days too weren't they? 
Sadly, the majority of the efforts by any companies are going to be targeted to the masses of able bodied persons, because that's where their greatest revenue potential is. I don't mean that disabled people cannot somehow afford their products, but just that they are looking for that hook. They don't just want you to buy a single product and then support it like Hubitat does. No, most are looking for either the purchase of many units or a recurring revenue stream. What I do find odd though, is that lack of companies dedicated to serving people with disabilities specifically in smart home. As you correctly state, they are the audience that can benefit most. What's a mere convenience to an able bodied person, could be an absolute blessing to a disable person.
In regard to Alexa speaking when a door is opened or a motion sensor is triggered, I do want to let you know that it is absolutely possible now and not too complicated. I just posted about this for someone else today.
Using the custom code, you can make any rule in HE trigger any response you want on Alexa. Hope you find that helpful.
