I'm not surprised at all that many of the players from that generation of Milan players have become managers (and very good ones!) and directors and even successful politicians (like Kaladze).
It was a very smart group of players and at the time Milan was a school... Ancelotti and the rest had learned the trade from Sacchi and Fabio Capello and they passed it on.
It's a bit of a shame that we couldn't make a smooth transition to another generation like we did from the 90's to the 00's now.
The 4 ex-players we used as manager had a lot of trouble who were not only their own, the ownership changed twice and will probably change again in a few years and you all know what was up.
Anyway I don't particularly care a lot about Milan being filled with ex-players. Though it's always nice have someone Maldini in a key role to rebuild the club. And I'm pretty sure more ex-players will join the next few years not because they used to play in Milan but because a lot of them are doing damn good work elsewhere.
I thought
Seedorf did well (though I'm quite biased when it comes to Clarence, as he was my favourite player). Considering that he literally retired as a player to take up the managerial position at a team that was struggling, Milan performed the 4th-best out of all teams only counting games that Seedorf was in charge (which included a 5-game win streak), just one point from 3rd place. It's just a shame that Berlusconi was literally wanking to how well Inzaghi did with the youth team and couldn't wait to kick out Seedorf in favour of Inzaghi.
In many ways,
Inzaghi was set up to fail at Milan before even his first game. Like you said, the ownership change and associated financial struggles meant that he was given a garbage team. Inexperienced managers will obviously make mistakes and Inzaghi made plenty of them...but the quality of the team can help counter that, and Inzaghi's Milan were really...really bad.
I have nothing to say about
Brocchi's Milan. So few games in charge and the team's fate under Mihajlovic was already sealed. This team suffered from the same problems as Inzaghi's team.
Rino. Much grinta and benefited from a more stable ownership that actually had some semblance of a plan going forward. I also thought that Gattuso did a fine job. The team was not strong and the attacking players couldn't score on a prostitute (Higuain was an incredible centre back for teams against Milan), yet they finished one point shy of Champions League qualification. In some ways, this is less surprising as Rino was the most experienced of the four.
I'm sure that all four would be better managers today had they not jumped on the Milan ship so early.