Because it creates too much friction at the point of transfer.
Decryption security should be handled in a way that the decouples user data from the device itself. There will always be theft. The impact that we have on the planet is something we can no longer afford to ignore.
This isn't an issue of turning off our brains. We have two problems we have an issue with theft and how security mechanisms that are tied directly to the device strongly prevents reuse and resale.