In my opinion, a national ID card would be economically sound if it did away with all other forms of identification. By doing away with all other forms of identification and putting everyone and every license and every security requirement and all social security and medical identification and all state identification could be eliminated as well there would be a huge cost savings.
Let's say you're like me: you work full time at a gas station that checks everyone's identification for alcohol or tobacco. You can only accept US Government issued ID's. So a Mexican man walks in and gets his beer, and comes to the front. "Identificacion, por favor," you say sweetly. He hands you his Mexican issued ID. You frown and explain you cannot accept his ID because it is not from the US. He sadly walks off and you lose a sale. I believe we should make everyone have to carry as US ID as long as they are in the US. That problem would have been avoided if that were a thing.