Correct me if I am wrong here, but would the following changes to SSH give you the same result:

Change protocol from TCP to UPD and port from 22 to 62201.

Remove greeting.

If first message is not the correct password, do not send a reply.

If everyone used this, do you think SSH would become more secure and eliminate password scanners? Personally I think that if ssh took in a fwknopd patch and used that as default, any benefit you see now would disappear. I also suspect that logging every UDP package to 62201 would be a bad idea, probably worse than logging every failed attempt on TCP port 22.