Even if such a hypothetical encryption scheme was not intrinsically weaker, it still requires two very strong assumptions:
1. Not a single individual with legal access to the interception system will ever abuse it for their own purposes, or in exchange for a significant bribe or under the threat of blackmail from a powerful and wealthy malignant actor.
2. A future government (democratically elected or not) will never decide that currently legal behaviour is now a crime which warrants interception—say possession of drugs for personal use, "deviant" sex, unpatriotic discourse, etc.