Littledave not sure I have ever come across the “very precise needs” of the disabled, we have very many different types of disabled on the scheme, from wheelchair bound to able bodied with mental health issues so It isn’t necessarily a one size fits all situation.
As with all businesses if the demand is not there they will not spend money, unless they are required to via guidelines from the government. My father in law was a taxi driver for a few decades and every week he picked up disabled adults and kids, taking them to hospital, school etc. So if a hackney taxi can cater for disabled then I’m sure with a bit of inventiveness they could cater for all.
The way things are it is likely an app would be produced where you can enter your specific needs and they could provide a vehicle to meet those needs and keep your details on file. They could have a series of vehicles on the app and you choose which one fits your needs.
You could book it like a taxi for a night out, with a time to come back for you, or book it for a fortnights holiday in Devon, or wherever lol.
You would be able to talk to the car or speak to a human in the control room. With no driver it would be extremely safe for female passengers not comfortable getting into a car with a stranger.
The benefits are many.