I'm going to assumed this is after you waited in line for a good 30 minutes, because the design of T7 itself prevents luggage off-loading to be on the belt as fast your statement would suggest.

Right now I sit at the first exit row of Y, and usually I'm the first batch of Y pax to get off the plane after the F/J pax. Walked straight up to the customs area (a good 2 minutes), maybe a little wait at the customs line (least amount of time I've waited is 2-3 minutes), and my record is probably that, within 10 minutes to the luggage belt, and then I can look forward to a long wait for the siren to go off indicating luggage is coming.

Now, I would say that JFK has been very very good in throwing out F/J bag tags first. But like I said, in my decades of flying only twice has they messed up the order (two luggages, one came out right away, another was one of the last ones to come out, both are tagged Business Priority.)