[Cthulhu_]

I suspect a major difference is that those e-scooters, bikes, cars, etc are produced and sold by the millions, whereas wheelchairs are small volume by comparison. Another commenter mentioned the legal requirements, which complicates things.

That said, a quick google says there's 65-132 million wheelchair users worldwide so it's not a small market either.

[nothercastle]

Most of them are probably in countries where 1000 is a years wages.

[space_oddity]

...but the production and distribution of wheelchairs