It's not a mystery at all. There is very limited hardware that will work with p2pool, and the choice is getting smaller every week. SP10's are out of stock, S1's are finished, S2's don't work, S3's probably won't either when they are released, KNC's have run dry or not being delivered, Dragons don't work etc, etc.....the list is endless. Hardware that does work will soon be out of date & unprofitable to run like the S1's, Chilis,etc, etc.

All the nodes in the world won't make a blind bit of difference if there is no hardware that will work with it.

Why is this you ask? Read the posts above. Mystery solved.

The sooner someone forks p2pool from the donation demanding invisible-dev here, the sooner the community can start developing p2pool to make it compatible with all the available mining hardware.