[cesarb]

> Government generates a public/private key pair Gpub/Gpriv [...]

Isn't that exactly the Clipper Chip scheme? The arguments against it are as valid now as they were then. If you haven't seen them before, they can be found at the 1997 paper "The Risks of Key Recovery, Key Escrow, and Trusted Third-Party Encryption", and its 2015 followup "Keys Under Doormats: Mandating insecurity by requiring government access to all data and communications".

[xyzzyz]

Not exactly the same, it offers slightly different trade-off between the benefits and the drawbacks. But yes, the idea is clearly not new or non-obvious. There are plenty arguments against doing that, and thank you for the references (I wasn't aware of the second one). Nevertheless, just because it has some (in fact, many) drawbacks, doesn't mean it's completely broken and useless, and that means that we shouldn't expect that something like this won't ever materialize.