Surely the world is full of examples of things which were considered OK and now are not? Lead in petrol was thought safe, cigarettes were thought safe, raw sewage dumped into rivers was though safe, CFCs in aerosols was thought safe. Extreme examples but does it never happen with electrical regulations where they say "this is no good, its not safe enough" and they change them?
Of course, and that's a point I very often make myself whenever people say (as some do repeatedly) that something which would have been compliant with
any previous edition of BS7671 should not be considered 'potentially dangerous' today.
However, I think you may be missing my point.
For a start, different from all the examples you cite, knowledge about electricity (and dangers associated with electricity) has not, in general, changed for very many decades (although our ability to address some of those dangers has changed because of technological advances - e.g. RCDs). What
has changed over time is 'our' view of what degree of risk is 'acceptable'.
However, just as something does not suddenly become dangerous because a new book of regulations is published, nor, in reality, does the view about 'acceptable levels of risk' change 'overnight', either.
The thing to realise is that (with just one very specific exception mentioned in guidance to the regulations) the coding of things on EICRs is
not (contrary to what many seem to think) about conformity (or non-conformity) with any regulations but, rather, is down to the inspector's judgement as to whether any such non-conformities do, or do not, represent "danger" (C1) or "potential danger" (C2). That is obviously an individual judgement, based on a number of factors. As I implied, if something would have been conformant with regs (hence considered to be "acceptably safe") 'last week', but not today (because a new set of regs has been published), that is one of the factors which an inspector may well take into consideration.
Kind Regards, John