Who cares if he has nostalgia for an older theatre culture? So do a lot of people- the majority, I'd think- who buy tickets to his productions. He's selling nostalgia as part of his brand. As far as I can tell his productions have done as well as any in the last decade in terms of bums in seats and excitement generated. I don't give a crap what his profit margins are and whether he'd make more doing viral alerts on Twitter than a two-page spread in The Times.
There's a hell of a lot of theatre today that I could easily dismiss as "silly" and I think that by not giving it the benefit of my doubt, it's ultimately me who is the poorer for it.
I don't know what age you are but I am making an assumption that you're young and I wonder whether you equate any person or play over 40 with "embarrassing" and "out-of-date"?