There are components of management culture which are fads, like the idea that one could be an effective manager, while not understanding what one's reports are doing, through some management-foo learned from books and blogs. The success of that fad is no doubt partially due to the economic climate. People want the tech industry money, but don't have the tech industry skills.

Leadership is timeless, humans have always organized themselves in groups with leaders, and we instinctively play the part of leader or follower according to the situation. Being a good leader just means allowing the group to accomplish something that would be less likely without one's guidance. Being a good follower is mostly a selection role, where one exercises judgement in choosing a leader to follow.

The mechanism for dealing with bad leaders has also changed relatively little: stop giving them your own resources, and put distance between you and them. In the workplace this is asking to switch to another team. You can dress it up with fake reasons, like you are interested in another project, or you aren't learning enough, whatever. The important thing is that it takes a resource (you) away from a bad leader and gives it to a better one. Iterate this process enough, and the incompetent leaders are outed through their inability to maintain personnel.

People don't do this enough, it's an easy way to signal to upper leadership who in management is bad at their job, without a direct accusation.

Yes. All leadership is supposed to be technical leadership. Outside of engineering-management, technical just means significant actual domain expertise. If you want an organization that can do stuff, you have to know stuff, there's just no substitute and everything else is basically fake. The "visionary", the "idea person", the experts at alignment / people / processes / ceremonies were always kind of mythical but to the extent they were ever real.. that kind of expertise tends to be removed in large orgs anyway because they are viewed as threatening by fakers who are better at maneuvering.

The fad is non-technical management, and the result is a general crisis in leadership that you can see everywhere across tech, politics, entertainment, whatever. Top leadership is out of ideas and just looking around for others to copy, or cruising on extraction/exploitation of value-creation that came before. It's a slow-motion disaster that's been picking up speed, which is why consumers, workers, and constituents are all pissed off. Seems like the shareholders will be effected soon, so then maybe it starts to change.