Which is why a lot of the real money is in products that have wide appeal for non-disabled users.

This is where most of the bizarre "as seen on TV" products come from: The inventor made a tool for people with disabilities, found that the target market wasn't large enough to sustain a business, and frantically tried to pivot. Pivoting is hard when you already have a large inventory of hard products.

If you can build something that able-bodied people are not only willing to use but willing to pay extra for, then you're good to go.