Re: OK, I'll bite
"If everyone has a smart phone, then everyone has their driving licence on them, so everyone effectively has an ID card on them."
Except, of course, not everyone has a driving licence amd/or a smartphone.
On the other hand, this move towards more and more digitla ID/digital only documents falls down when you need to present two forms of identification, one must by photo ID at various places such banks when opening an account, or dealing with a deceased affairs and they must by original, printed hardcopy documents.
With no passport, no driving licence and all the household bills in my name, the only way to get around "the system" when my wife wanted to change her bank account to same bank as me, on the advice of the bank manager, we opened a joint account then made an application for my name to be removed from the new joint account. Then we opened another joint account so we eventually got what we wanted :-)