At larger companies, data retention policies that delete old data are pretty standard for platforms like this. A lot of them can harbor conversations that can be taken out of context or were never meant to be public, so it makes sense from a liability standpoint.

That said, there can also be a large body of fruitful technical knowledge sharing that happens on these platforms that should be retained for the good of the company.

The real rub is throwing the baby out with the bathwater. How can the signal be isolated/retained/copied easily so the noise can be purged? This is especially difficult for very old data that is spread across innumerable channels whose value could be lost and the team left unawares.