Salesforce rapidly enhanced Flow’s functionality and encouraged all its customers to move from Process Builder and Workflow Rules.
During Dreamforce ‘21, Patrick Stokes, the Product Manager responsible for retiring Process Builder and Workflow Rules, explained that an end-of-life council would govern a formal end-of-life roadmap.

Do not panic! The retirement process is challenging; it is planned in different phases over the years, not months. It is a gradual process that helps all its customers accommodate the new tools and get accustomed to updated features.

According to Salesforce’s latest update, a roadmap projecting the gradual process of the retirement cycle can be seen in the illustration below: