Getting chosen to work on high visibility features and creating new products seems contrary to what most people qualify as “incompetent”.

Now all you are describing feels more like a Product Owner’s job than a manager.

But even putting that aside, employees also want a manager that makes their group look good, takes high visibility jobs and is good at politics. Having a successful manager greatly helps to get promoted, even if that manager tries to take all the credit. Also nowadays peer reviewing is pretty standard, it’s a lot more credible to present oneself as a good manager of a good team.