That proves that it doesn't even matter how good history in your career as a footballer and there is no guarantee if you will be a good coach. In fact, so numerous players that shifted to be a new coach were only a few that was successfully become good coach.
A general pattern. There are very few former world-class players who have become successful coaches. Most of them have had one or two stints as a coach and then never found a job as a coach again. Wayne Rooney is also very unlikely to become a successful coach. Much more successful are former players who have played in the first or second division of their country, but have never really been among the greatest. The best examples of those are Carlo Angelotti and Jurgen Klopp.
Actually, it's not a general pattern. I think the most basic thing is whether he retired because he had a bad career at the end of his time?
Because most of these players will decline their careers as they approach retirement, move to small clubs or even minor league castes, and then take coaching courses.
This pattern will result in more failures, compared to players who retire during their glory days.
Unfortunately I see that Rooney doesn't have a vision for that, I just think he will become a coach and take advantage of the big name he had during his career at Man United. Maybe we can compare it with Gattuso.