I can see what you mean about Americentric, I suppose my general point was that it was pretty much very Euro-American centric in that even the Americanness is a very distinct middle to upper-middle class white American sensibility. Whether it's their choice of theater or music, there's definitely a tendency to overplay the old European stuff at the expense of nigh everything else.
It does seem odd when you stop to think about it, that most people in the
Star Trek universe tend to enjoy what we (as 21st century folks) might consider "classical" entertainment - Mozart, Beethoven, Dickens, Conan Doyle etc - rather than what might be "classical" to them as 23rd/24th century people.
Apart from Riker's love of jazz, Tom Paris liking cartoons from the 40's and Kirk's references to 70's writers Jacqueline Susann and Harold Robbins, off the top of my head I can't think of I can't think of other examples of more modern (or non-American) "theater or music" in
Star Trek.
But why is that? It's a real world reason: Mozart et al are all old enough that people making a TV series won't have to worry about rights issues if they want to put some of it on their show. The same wouldn't apply to The Beatles or U2, for example. That's why Harry Kim's holoprogram in
Voyager's "Heroes and Demons" could be
Beowulf but not, say,
The Lord of the Rings.
I think this, plus the fact that the people writing
Star Trek shows were informed by the scope of their own cultural experience (the "distinct middle to upper-middle class white American sensibility" you mention) is one of the reasons why characters in
Star Trek (on TV) come off as culturally slanted toward pre-20th century "eurocentric" culture, when realistically they wouldn't be so narrow.
Unless of course, all the records of cool entertainment from our era were destroyed in the Eugenics Wars...