Afterall google tries to give a good final user experience, if the websites are crap and just for the purpose of ranking i guess sooner or later they will be penalized. Maybe not now with an update but in future.
SEO is always grey hat cuz you want to rank , trade marks buy sponsored articles links ect , newbies does same. SEO It s about links mostly ( many other factors ) if i am not wrong so master a quality link (website), Do a PBN as if it were your only webpage ur baby , good content good user experience etc.
In order to make money you need money and hard work.
If a good quality PBN is hit by any penguin update but have a lot of people interested in its content or suscribers it will contine to have "organic traffic" so in the eyes of any is a good site and will rank again.
All the other may be Churn and burn ones that does not rank inmediatly and when it does ... only for months or a year.
Of course will be blackhatters having his own secret sauce, we will never find until it is obsolete, once you find those ranking just do reverse enginiering try to rank different niches with that method and will last longer that any public method ( the ones that are becoming obsolete ).