It's entirely possible – I drew up a spec of what it could look like a while ago: https://docs.google.com/document/d/1BsOd4PXQ0SfsdMP0n30Ud_Aa...

The only issue with it is that the decision to give everyone a developer certificate for free was to increase Swift adoption. The security implications were not investigated. Apple wasn't aware that they put the final piece of the puzzle in place for something like this to exist.

They can easily reverse the policy.