How to describe something that continues after the conditions that led to it no longer exist?

Question

Q1. Is there a phrase to describe something that is formed or done in response to conditions or circumstances, but which continues after those conditions or circumstance are no longer applicable?

Q2. If there is not a common English phrase for this, is there any technical term (e.g., from physics) that might have metaphorical value (i.e., in the way the mathematical term ‘asymptotic’ is sometimes used to describe chasing something but never catching it)?

Examples of what I am trying to describe:

• ‘It is the same with God: even when we no longer believe, we continue to believe that we believe.’ — Jean Baudrillard, The Gulf War did not take place
• The moment in a lava lamp where a blob breaks off from the base and floats away on its own.
• Oxfam formed as the Oxford Committee for Famine Relief in response to a famine in Nazi-occupied Greece, but continues today
• A police force formed along the line of 'the police being only members of the public who are paid to give full-time attention to duties which are incumbent on every citizen', but which have become so large, powerful and specialised to the point that they become distinct from the average citizenry.
• (controversially) Continued adherence to traditional religious cosmologies and folk remedies in the light of more convincing explanations and efficacious treatments (i.e., hewing to pre-scientific methods).

Terms that I don't think quite apply:

• ‘archaic’ - just because something is old-fashioned doesn't mean its original context doesn't apply
• ‘outdated’ - close, but I don't think it fully captures the idea of something being untethered from its cause of origin
• ‘zombie’ - seems too negative, and could also just refer to an organisation acting zombielike (i.e., not thinking)
• ‘mission creep’ - I think that what I'm after is a subset of mission creep, but that that term itself does not imply the loss of original conditions on its own.

Answer 1

While searching, I made notes, and I figured I might as well leave them since you seem to be looking for synonyms that are appropriate within a certain context:

• Persistent, lingering and unremitting are somewhat decent candidates, but they don't necessarily imply the cause has disappeared.

• Inexorable emphasises the impossibility of it stopping, but still says nothing about the cause.

• Inveterate could be what you are looking for, but is used mostly in a medical sense, pertaining to addictions, illnesses, or diseases (similar to chronic).

• I think entrenched might be closest to what you're looking for:

  to firmly establish something, especially an idea or a problem, so that it cannot be changed
  [Cambridge]

Answer 2

In IT we use the word legacy to describe software or hardware which is still in use but, in terms of technology or modern practice, is otherwise considered obsolete. It is still performing its original purpose and often would be too expensive to replace with a more modern solution, although it was a reasonable solution considering the conditions and technology at the time.

In computing, a legacy system is an old method, technology, computer system, or application program, "of, relating to, or being a previous or outdated computer system," yet still in use. Wikipedia - Legacy System

Answer 3

I will propose ‘Goodharted’ as an option, after Goodhart's law:

When a measure becomes a target, it ceases to be a good measure.

i.e., a measure implementened to track a particular feature becomes a target, continuing to be tracked but no longer measuring the same thing as initially.

Answer 4

In answer to the title of the question, as well as one sense of most of the body of the question, the adjective used to describe such a thing is self-sufficient:

1 : able to maintain oneself or itself without outside aid : capable of providing for one's own needs

// a self-sufficient farm

In short, its continued existence is no longer based on those things that were required to bring it into being—and it is able to now maintain an independent existence.