Why would I imagine that? There are privacy implications, but a unique ID doesn't mean everyone has access to all your data at any time for any reason.
Imagine someone steals your driver's license. No biggie.
Now imagine they steal your identity which is linked to everything you ever do.
No they don't. If they breach the health system, they don't have access to tax returns.
Just because people are identified by a single ID number doesn't mean all their data is being stored on the same server. And for purely organizational reasons, that's incredibly unlikely to happen.
And I don't know what you mean by "steal your identity". People's names are date of birth are generally a pretty unique identifier already. It doesn't really matter if systems use that or a single ID number to identify you, or if hackers look you up by your name.
Has cybercrime been rendered obsolete with a government credential? Why is this master account immune to theft? On the contrary, it appears to be a credential that once stolen, could be more impactful than having your primary email account and phone compromised.
It's reasonable to be concerned even just from an infosec perspective.
I'm trying to understand if it is speculative or if we have a base-rate for occurrence.
The subject was a system being breached.
And the account you set up for a driver's license is generally different from the one for your health care. If you're reusing the same password for both it doesn't matter if they're linked by the same digital ID number or the same email address or just the same name and birthday.
A digital ID number isn't changing anything here.
Which is why you have completely separate account to pay the same government for crossing one specific brige in East London than you do for vehicle tax.
Most government websites do use the same frontend toolkit (a rare win for UK governmental IT) but front completely separate systems.
Card = one person, limited use.
But most importantly: a Hitler rises to power = opposition is screwed.
If a Hitler rises to power you will be screwed with or without an ID card, so please don't use such a silly argument.