This type of story about management getting rid of the old guard is so common and typical, it remains one of the most frustrating aspects of this industry.
In the “enterprise scene”, this sort of purge strategy is likely linked to a big percentage of money wasted and sometimes total failure.
Why do managers keep making this mistake? “Legacy” is only a bad word in IT. :-(
On the other hand, it is not uncommon for the exiled old guard to form new companies, teams, products and realize their vision under new management.
It is not like their knowledge and experience gets literally purged.