Language change is influenced by several things, in both a conservative and a innovative direction. Input from older versions of the languages demonstrably has an effect in holding back language change — or at least, in promoting use of the older version’s features in parallel.
- Outright reversing language change doesn’t happen that often, and needs special circumstances—like with Icelandic and flæmeli (small population, universal literacy). Conservative influence however has a lower threshold for success.
But the success of conservative influence is incidental to it being older. The real reason why any conservative input would be successful is that it is being held up as prestigious. This is what happens with standard literary versions of languages: they happen to be more conservative than spoken variants of languages, but they influence language change because they are held up as prestigious, particularly in education.
So for old recordings to influence language change, it is not enough that they become available. They would need to be actively promoted in mass education as models to be emulated. In western culture at least that seems unlikely.
One area where recordings have much more of an impact is language revival efforts. In that context, knowing what your ancestors’ native accent was like is very important, though it may not be enough for you to shake off your modern accent…