We've had bad managers for a long time. The situation has gotten worse as the workplace has shifted from manufacturing to the knowledge work. The biggest culprit to keeping managers from adjusting to the new reality is the flat organization.
The thinking behind the flat organization is simple: managers are a barrier between the C-suite (where strategy and thinking occurs) and the workers (who have to execute the strategy). If you get rid of the barrier, you reduce or eliminate any issues. Makes sense.
Except it doesn't solve anything, in fact, it makes things worse. See the strategy that comes from the C-Suite is often difficult to understand, which makes it difficult to execute with any consistency at all. Second, it assumes that the worker simply wants to know what to do and be left alone to do it. Which is a mistake - they do want to be left alone to do the work, but they also want a coach, mentor, and someone who can provide high-quality feedback. The best person for that - someone in a manager role that adapts to the reality of the knowledge workforce.
What flat orgs also did was turn the current managers into glorified individual contributors. These individuals were worried about doing work, and managing was something that they did when they had time (or were forced to by HR). Of course they were bad - who wants to get good at the part of the job that no one values?
We don't need to eliminate managers, we need to make them better.