I don't understand why it isn't feasible just to "tag" a piece of ID (e.g. a machine readable or biometric passport, or a frequent flyer card) with flight details, so this is scanned at the gate with no need to bother with a pointless piece of paper or something that risks becoming useless if your battery fails.

Yes, some people might want a printout of departure times, but if they do they can just print their itinerary or view that on their phone.

As a boarding pass these days just contains a barcode referring to a record in a database, and as *some form* of ID is generally required to fly (with very few exceptions) and must generally be shown at the gate, I really don't see there as being any need for one at all, particularly not on "low cost" airlines where no seat assignment needs to be recorded.

Neil