Snapchat’s founding principle and only differentiator from day one has been untrusted client security. There were way too many years where the general public believed that a Snapchat could not be saved. I give huge credit to Snapchat for accidentally teaching the public that if human eyeballs can see something, it can be recorded forever. Now that is taken for granted, even last week’s Saturday Night Live TV sketch referenced what a fundamentally flawed security model Snapchat has.
What? That wasn't a principle of theirs. They explicitly exclude "screenshot detection avoidance" from their bug bounty policy: https://hackerone.com/snapchat?type=team . They always have. As far as they're concerned, that's not a security issue.