My rMBP is a Nvidiagate 2.0 candidate, but never had issues to ask for a fix. However, I've already had replaced for free on my early-2013 rMBP:
1. Display, due to the coating-gate;
2. Top-case, due to defective battery;
Both fixes were done in 2018, about 1,5 years of expiration of my AppleCare extended warranty (Dec-2013 to Dec-2016). So, again, I never had big issues with Apple support. A friend had an iMac 2011 with defective GPU fixed for free a couple of years ago. I had a white Macbook with a melted rubberish bottom case fixed way after warranty expired.
Really don't understand what kind of dialogue people are keep with Apple support... and I'm in Brazil, where consumer rights are usually in a lower standard than USA or most of Europe.