I would like to start from the bottom…
Thank you @nadia for pointing this out 
This is an interesting post, touching on a number of open questions, some receiving partial implicit answers in the same text, others remaining open at all.
I would like to start from the bottom of it. Transforming patients (or their closest carers) into makers is an interesting perspective. We know from citizen science that this first hands involvement often offers a stimulus to personal studies, and reflection about the identity of the problem, and the problem holder. One could argue this is an even more important potential benefit than the access to the devices in itself.
However, an important reflection should happen about quality and safety. If one cannot bring a simple solution to the market because of the iters for safety and quality certification, and this we agree is bad, the solution should not be “ok, let’s ignore this step and bypass it”.
There are a number of issues here. 1st and foremost, one has to describe how safety and quality are reasonably assured, and what safety net would be put in place should something still happen (although we know they are not perfect, to use an euphemism, today a number of tools and services exist to cover for assistance, accidents’ costs, etc on the side of providers).
Of course, one could ignore this. Depending on the IP scheme, no safety nets would be needed (although it would nice to think of them), for example. But this brings us to a second issue, one that is almost “ethical”: transforming every patient in a maker can leverage the citizen-scientist effect only if (this is presented as gut feeling here, but I am open to discuss it in depth later) the right IP scheme is adopted. And only if radical openness is adopted one can truly claim no responsibility over the final “accidents” that will always happen (only that which does not work, will not break). Should the creator preserve control of the IP for itself, one will always find a court that will consider the business model “exploitative”, and enforce the order to establish the aforementioned safety nets (there is an interesting case about a fire happend in an AirBnB apartment that touches on this topic)… falling back to the problem one wanted to work around, just a bit later.
So, what would be the general ecosystem’ services that would keep this garden grow orderly? I don’t see this answered (that’s not an easy one, indeed)
Research, and “citizen science”, target the pioneers and early adopters… To scale beyond that, we need to think the entire ecosystem, and be humble.
For the sake of our understanding, let me be pedant and allow me to stress that disabilities do not exist in silos. People have many things going on in their lives, and around them, of course also the disabled ones. They do not stop living when they change status. A few will want to pioneer, some will want to have new solutions, some others will not want any because… I am not sure they need a “because”.
I would like to not dig too deep in the question about why the current “solutions” are often not marketed/offered… just for the sake of reasoning together: if you had a clue about how to build an engine, and it would work once every 100 attempts after serious tinkering… would you be able to market it? Let’s be honest with ourselves and remember that researchers are very optimistic people (I belong to the category, so this is self-criticism). They will produce proof of concepts, hardly ever demonstrators (although they usually confuse the terminology), and they don’t normally ask themselves questions like “how long will this work continuously?”, “what will be the safety mechanism once it turns off, as instance because of battery exhaustion?”, how many scenarios are realistically recapitulated in the lab I used for the tests, and how well does this solution generalize?",…
Let’s not dive in the argument of healthcare provision on this topic. Sometimes it is the right reflection to face, some other it is populistic… In these circumstances it reminds of the sentence I have recently read on twitter “being poor means having too much end of the month”… it may steal a smile, but it’s a classic example of ill-posedness. You will not solve poverty by trying to shorten the calendar.