Why is reuse so difficult?

Most countries have established e-society strategies aiming at ao providing public sector services via the Internet. Progress has generally been fast with general information sharing  - but when it comes to private information (health, tax, social benefits, school records etc) - not to talk about signing documents - progress is generally stopped due to a perceived lack of tools.

In several countries it has luckily been realised realised, that reusing e-bank sign-in credentials - for both strong id and signing (I just established a limited company with 5 shareholders - no paper) -  not only in other private sector but especially public sector services is a key accelerator for e-society migration. To reuse means that ready trust and big volume habits can be built on > fast adoption - in addition to saving hundreds of millions (should this not be in strongest focus these days?).

Listing benefits:

- ready high volume habit (10-15 times more usage of strong tool - than all other potential cases taken together)  > economy of repetition (exponentially growing value in fragmenting world) and economy of scale

- the tool has to be strong enough for banking (supervision in place) = strong enough for any use

- tool can be used both for id and signing documents (can also provide age)- the tool has already been invested in  > economy of reuse

- banks are trusted (in this aspect at least..)  > economy of trust

-  banks as service providers have to adhere to anti-money laundering legislation anyway when opening accounts and handing over e-id tool

- banks provide the service also to unbanked

- payback time for banks - they should do this as good-for-society-at-large (income will not be big - but can cover the costs with some margin)

So why is reuse so difficult to spread faster? Why do tax payers not demand it? Why is it accepted that the public sector invests huge amounts in always-failing separate credentials? Anybody in the know?