The immortal surgery will never be used at all for sure I would say.
It would be great plot twist if we get to know...every SH died in childhood...Sanji died and was replaced with some other child who was normal, luffy died in childhood as soon as he ate the DF, zoro died in the serious battle against kuina because of which kuina also became sad and died in an accident, nami was killed after refusing to work for arlong, robin never made out of ohara, chopper was dead and his nose turned blue due to decomposition thats why he was rejected, franky is not human but 100% artificial, brook was attracted to them because they were all dead.