> Quite a few IDs contain a 2D barcode, and I believe at least some of these contain some offline-validateable signature over the basic data of the document, including the expiry date. That's not as trivial to forge.

Most government IDs don't have that, and it's still not clear what good it would be doing when data breaches happen on much shorter timescales than ID expirations. Who cares if they stop being able to use the ID after 10 years, when they can use them for 10 years and there will be another breach providing them with a new batch of IDs to use in a matter of days rather than years?

> On top of that, document expiry does help a bit with people trying to use a lost/stolen ID of somebody they happen to look similar to

That seems like an extremely narrow advantage. If they just need some ID that looks like them then they can just get another one from the batch of fresh ones. If they need the ID of a specific person, the government still isn't authenticating renewals, so wouldn't they just use the existing stolen ID and pay for a renewal in that case, in which case we're back the only thing happening being the government extracts money?

Or no, in that case it's worse, because then they can submit a fresh picture of themselves to renew the ID which has someone else's name on it.

> adds a forcing function to make people eventually upgrade to newer/more secure document standards etc.

Which you already have because everybody eventually dies.