Basically IATA doesn't allow any paper tickets to be charged through their Billing and Settlement Plan. This means that a travel agency i.e. cannot issue any paper tickets, since they will not be able to proceed with the payment through the BSP.
Nevertheless basically every airline can still issue themselves Paper Tickets on their own stock, since if the airline issues the ticket themselves, they don't need to use the BSP, as they already collected the money directly from the client without the need to use the BSP. I don't know for the US, but here in Europe this will be done only in some very rare cases, i.e. when there is a constellation of different airlines that don't allow interline e-ticketing. But this is almost non-existent anymore (this was still an issue at the beginning of the paper ticket ban by IATA, i.e. when Infant-Tickets were issued). The only case I know where Paper Tickets are issued is in Germany when a train ticket is involved (i.e. American Airlines which sells german rail tickets i.e. from NUE to FRA with AA-flight number) since German rails want a ticket coupon to keep for their account (i'm not talking about Rail&Fly, I mean a very specific train with AA-flight number).
Sometimes you will get a paper ticket on the spot as well, in case of an irregularity, but this is mostly a Flight interruption manifest and therefore not exactly the same.