The root cause of identity theft in USA and some other places is the lack of "proper" national identity and the associated use of various personal "secrets" (not that secret) for identity verification because there are no good easy other ways.

Businesses in Scandinavia and many other countries would not treat someone knowing your personal information as any evidence of identity (because it's not); having all that information is not sufficient to impersonate you there - identity theft does happen but it would require stealing or forging physical documents or actual credentials to things like bank accounts; knowing all of what your mother or spouse would know is not enough to e.g. get credit or get valuable goods in your name.

The US has no single national photo + chip ID card that is available to everybody, for free, including illegal and semi-illegal immigrants and homeless people with no access to their birth certificate and such.

It's completely crazy to me that you can be "out of status" with the USCIS and still get a social security card and a bank account, for example.