Not everyone who struggles to walk more than 20 feet wants to use a scooter (or can even afford one), many elderly people in that situation already have a car, and many of them are able to drive relatively safely. Like people with respiratory or heart issues.

And right now they have the option to use a mobility scooter or a car, if they lose the option to use a car then there will be places that will take a lot longer to get to. I think it's reasonable for people like this to prefer being able to drive everywhere, it gives a huge amount of independence and is clearly can be more convenient than public transport.

And there is a dignity aspect as well, I don't know how seriously people will take that argument but I understand that many older people would avoid doing trips rather than using a mobility scooter. I think that deserves consideration as well.