There should never be any process acting against the user's interests on a device that they own. Ever. Full stop. The only reasonable option is to do full encryption on the device without any system that allows inspection or identification of the material being encrypted. It didn't matter that vouchers enabled the decryption of the material after a threshold was hit. There would have been logic running on everyone's device acting as a snitch. At some point that functionality would be expanded and abused.
Your optimistic point of view does not align with the reality of how this kind of technical capability becomes misused over time. The ones that create these things are not the ones that control them 20 years later.