Not sure about all the misinformation in this thread...
We have several clients that purchase hundreds of expired domains per week from us and are systematically turning them into PBN sites. These are clients in some of the most lucrative industries in the world and generating millions of dollars per month in affiliate commissions.
These aren't affiliate guys working from their bedroom, but are actual corporations registered offshore consisting of teams that are dedicated to dominating the SERP's through blackhat SEO.
Their entire revenue is from SEO affiliate commissions, driven by black hat PBN's.
If Google's algo even hinted at resetting domain power at the expiration date, we'd know about it.
Expired domains for PBN have never worked better or generated higher ROI than what they do right now.