There are some incentive misalignments. Each AS that configures it is doing it to protect its neighbors, and does not benefit from itself having configured this

There are some incentive misalignments. Each AS that configures it is doing it to protect its neighbors, and does not benefit from itself having configured this way. Best practice suggestions only go so far. Another aspect is, if you configure it not just with your own prefixes but also that of your peers and downstreams (and their downstreams etc), then you need a source of ground truth. (Remember that not all ASes need to announce everything they have, all the time.) This is usually an out of band database. Then you have the problem of database needing to verify the truth, and keeping all the data fresh, etc.