This way of thinking is absolutely still around. I think AI may actually be making it worse. Now managers have it to validate their ideas and they don't think they have to listen to feedback from subordinates because some AI agrees with them.
I've spent a few months building a simple feature management system for .NET - https://featureflags.app. The .NET built in feature management libraries work pretty well. But I wanted an easy to use UI for configuring flags - without having to use Azure.