And this might be part of the hold-up. Keep in mind that PBS stations are often funded through on-air drives. Some states have state-wide PBS systems that raise funds centrally. I believe in some states that is not the case. Carriage means funding for these stations, so they are more protective than local network stations.
I am fortunate in that there are multiple PBS stations available OTA. But blaming DirecTV for this confusion alone is not appropriate. You think DMA maps are confusing? Figure out which PBS station covers every house in the US.
Aside from the sheer number of options, would it make more sense then to simply do LIL for PBS just like the other net's?