I do not agree with Carlos. That is, different opinions from mine are legitimate, but I see it in a different way.
I think that today in Italian opera houses there are few opportunities to produce beautiful Wagnerian spectacles, due to a lack of money (staging Wagner is heavy and Wagnerian casts are few), due to musical deficiencies in the orchestras, due to musical deficiencies in the conductors, and due to deficiencies in the audience.
La Scala can afford it and must do so. Especially from a production perspective.
That is, an explanation for those who perhaps do not know how some things work in the theater. An opera can be a new production or a revival. If I do a new production, I conceive a show from scratch, with new sets, new costumes, and new direction. If I revive a show, I already have the costumes and the sets; I will hire a director who will stage the show but who will not conceive anything new. Theaters like La Scala have dozens of excellent productions already in their repertoire. Many of these are revived, especially when talking about operas with great public appeal, namely Verdi, Rossini, Donizetti... a revival costs less than a production, but some revivals become a sign of a theater's success.
At Sant'Ambrogio, new productions are staged. And regarding new productions of, I don't know, Otello or Aida or Il Trovatore, I don't feel the need. La Scala has done them all in recent years, and they were more than decent. What La Scala is doing in these years, instead, are new Wagner productions, which are being very successful. Tristan und Isolde has already been revived several times, and this year's Tetralogy is entirely a revival. Rather than another Rigoletto, I prefer Lohengrin. Moreover, it should be a beautiful Lohengrin, because it probably has the best cast possible today (or at least one of the best), and playing Wagner to Italian orchestras can only do them good.
Even more so (and here do not read my message as a response to Carlos, because it is not) I do not like the attitude of many "well-to-do" Milanese who see Lissner-Barenboim's choices as an insult to the city. The theater reflects the city but is not owned by the city. Milan today is not made up of the Milanese of yesteryear; it is a cosmopolitan city that is trying to modernize itself once again after a sad recent past of non-existent cultural policies. La Scala is facing a change in audience that is succeeding, and I am happy, like Lissner, that there has been public success among young people. I do not think that, in this sense, a comparison can be made between "Lohengrin" and "Carmen"; many of my friends would go to see Carmen paying out of their own pockets and would not go to see Lohengrin even for free. If a sell-out is achieved today at the (highly criticized) premiere of La Scala's opening, it is also thanks to Lissner.