Enterprise Archeology

Here is another attempt to try and define a 'law' that i have observed in multiple organisations.

In any sufficiently long-lived organisation, all change initiatives will incur an increasingly significant overhead caused by unpicking the detritus accumulated through previous initiatives - me

If this statement is accurate, then an important skill required within long lived organisations is, what i would term Enterprise Archeology, the ability to dig through the sub-surface of an organisation and make sense and contextualise the broken or half-missing artefacts of previous civilisations.

What drives the need for Enterprise Archeology and the wasteful effort that goes into it?

As someone with experience in Enterprise Architecture i might immediately leap to 'a lack of enterprise architecture', but i think thats only part of the story. What for you would drive the need for Enterprise Archeology?