Standardized roles don't exist in any industry anywhere, and from both sides to be incentive is there to fudge responsibilities. From a business perspective, advertising for current trends makes talented applicants more likely to apply. On the flip side, an applicant likely wants to have a DevOps title even if they are simply doing clickops, as it makes them more appealing later down the line with 4+years experience in the title. "Title inflation" happens in all industries - you see it with people being called senior engineers with 2-3 years of experience, for example.