I haven’t read the whole thread because it is likely to have a mixture of responses, but what I will say is that every disability is diffferent, and for some there are institutions who get it wrong, and in others there are, dare I say it, parents who have limited expectations. And I’m not just talking about learning difficulties but physical disabilities as well.
I am visually impaired. My parents never prevented me from doing anything. For my 3rd birthday I apparently said I wanted a bike, and loads of their friends sighed and said how sad it was that I could never have a bike, and my mum’s view was that if I wanted a bike, then why not. So I got a bike, had my stabilisers removed at some point, rode around our street, didn’t do any damage to myself or the neighbours, had roller scates, did damage to myself but nothing anyone else wouldn’t have done.
When I was a baby my mum read an article in a magazine about twins who were blind. These twins were pictured sitting in the middle of a mat, they were hugely overweight, and the article talked about how blind children never crawled because they didn’t have anything to crawl to. Well that is complete bollocks obviously.
At school the blind children who could do the least amount for themselves were the day pupils. These were children who couldn’t cut up their own food, who couldn’t pour a glass of water even in some instances, and who had no sense of mobility. Many of these children are now my age and still living with their parents.
But then on the other side we have organisations like the RNIB who, in at least one of their job adverts, state that “applicants should be aware that there may be blind people on the interview panel.” Actually they may have revised that to visually impaired but the intent is the same. If someone put “applicants should be aware there may be women on the panel, or black people,” there would be national outcry. But for some reason people applying to a charity who deal with visual impairment need to be made aware that they may have to be interviewed by a blind person. I questioned this on one of their FB groups, and was subsequently banned for doing so. 
We need to always treat every person as an individual first, rather than as a disabled person first. Only that way can we bring out everyone’s true potential.
PS: I quite fancy a go on an e-scooter. I just need an empty car park and a willing individual…. 