Mou's net spend in his first season was 58m Euros. Not really that much considering he got Ozil, Khedira, Canales, Di Maria and Carvalho. In his second it was 46m Euros, and he got Sahin, Altintop, Callejon, Varane and Coentrao for that.
This season, their net spend was one million Euros. One. It's a myth that Mourinho has spent absolutely ludicrous amounts of money. Just over 100m Euros over three seasons at Real Madrid really isn't that much, considering the amount of players they've brought in.
In comparison Barcelona's net spend over the same period is 78m, Bayern's is around 100m as well. Bayern have won one league title and no Champions Leagues in that period, the same as Real Madrid and are probably the strongest team they've ever had. Barcelona's first year of that period was also the strongest team they've ever had and they've won two league titles and one Champions League. Better than Madrid, sure, but no league title last year and no Champions Leagues in the last two seasons. All three of their records have been identical over the last two seasons (if Bayern don't win the CL), with Mourinho counting two domestic cups as well providing he beats Atletico.
He hasn't failed. He's come up against the best team in the world in his first season, went out in an even match against Bayern and won the league in his second, and has come up against a Dortmund team where it just seems like their time, like Chelsea last year. The Malaga goals, the narrow lack of remuntada tonight, the manager, Gotze and Lewa's potential swansongs, the togetherness, the peaking at exactly the right time.
He hasn't failed by a long shot for me. Not at all. Not to count internal strife, the press, Messi, the egos at the club, the hierarchies within the club. He's done as good a job as he can over three years.