It’s not a promotion. It’s an entirely different job. You now manage people, influence and have control over their careers, performance management, as well as obviously working budgets, roadmap, etc.
In my opinion, it’s a downgrade. I’ve found few managers in my career to be effective leaders. Most of my managers relied on the senior engineers to essentially drive the roadmap, do the estimates, lead design, break down the work, delegate, and lead the implementation.
This is generally the trend I see at Amazon at least. The managers who are good are extremely driven and dive super deep into the tech, while showing humility and empathy. They grow their people, get them the right opportunities, and are people you want to be around.
But there are waaaayyy too many managers who simply can’t cut it as engineers and switch from the engineering path to manager path. These folks actually add very little value.
Actually the best managers I’ve worked with are all former engineers who didn’t want to become managers but took on the role because they knew they could fulfill the need.