Was it a fad:

Zero Trust seems to no longer command the volume of articles that once set it up as a trend that promised a bright new future for security. This is in part because security is a journey. Rushed implementations and low returns often result in burnout with new technology

I don't think so - check out my blog talking more about it here: https://www.tripwire.com/state-of-security/security-journeys-change-management-compliance