Granted.

Everyone becomes immortal, and all mortal things in society become pointless.

All pre-immortality social orders are disbanded, social convictions and constructs (gender, sexuality, relationships, love..) are something of the past.

Over time people start embracing nihilism as the one true reading of the world: "Nothing matters". Empathy between humans slowly dies off.

The extreme behaviours grow, as people become either hedonists or stoics.

Hedonists live for pleasure and pain; common practices amomg this group are hyper-sexuality, heavy drug use and masochism.

Stoics seek to understand the reality they are in, either through science, pseudo-science, philosophy or art. Stoics live in chastity and isolation.

Eventually, either a stoic full of curiosity or a hedonist full of boredom finds a way to detonate some or all the active nuclear warheads, destroying the Earth and sending all humans to space.

Humanity is now doomed to rotate around the Sun for all eternity.