I've seen managers ride out perpetually failing projects that haven't made meaningful progress in years, team 'decisions' that are reliably and demonstrably bad, services that cost a fortune to run and have a slew of problems and unhappy customers, and rock-bottom scores in anonymous surveys. None of this matters. Essentially your job as a manager is to take credit, dodge accountability, and expand your empire(headcount) as to maneuver yourself towards the better high-visibility projects. Just like politicians, unless they're overtly bad(and even then) it's difficult to separate them from the sprawling cybernetic organism so you just kind of shrug. Maybe a team's success is because of the manager, maybe it is in spite of them or vice versa - no way to know.