Random thought: taking care of handicapped folks

The US government takes care of its handicapped people like probably no other country does. Right from reserved handicapped seats in public transport, sidewalks with ramps at intersections for easy wheelchair maneouvering, lifts (elevators as we call them in the US) with Braille on the buttons to sophisticated wheelchair-lifts in public buses. But I wonder how and why is it that the government does not think of having different sizes for different denominations of dollar notes so that it would benefit the blind.