For the "what's happened to Mourinho" thing, I think it's much to do with the evolution of the game.
He was, and is still, a very good manager and something of a personality. Football is now like that WWE thing - an entertainment industry before a sport. Because of this, I believe he plays a role (I think even SAF said Mourinho is totally different outside of football), and this makes him marketable in a way that Wenger just isn't.
On a footballing side, I think Pochettino has brought a catalyst to the game. Mourinho/AVB have come from the "Not a footballer but a thinker" stable, where they could out-tactic your Harry Redknapps, David Moyeses and Steve Bruces, who don't care for that much preparation. Poch has brought this idea of being a young and enterprising manager who can provide solutions that just aren't on the radar of these blokes (AVB/JM) who haven't played the game at a top level.
Add into that too the people like Alex Neil and Eddie Howe, who are bringing this fresh new approach of fluidly changing the team style depending on the opponent, and you've essentially got just an all-round higher level of management standard than you had in 2004. I think it's the same reason why Wenger and Rodgers (another AVB/Mourinho type) struggled and Liverpool haven't moved forwards until Klopp came in.
Mourinho, much like AVB, made their career as serial winners, and they just never learnt how to lose. They just don't know how to cope with it and seem to implode rapidly under the pressure of a loss they can't fathom.