I have just finished reading this book by Geoffrey Ashe in The Made Simple Series -a series of self education books. Although this book was written about 40 years ago, the book makes a point that made a great deal of sense but never occurred to me that you have to be writing in tune with the mood of today's society, not the mood of society 50 years ago, however well written your your submitted work might be, if your work is to stand a chance of having it published or used on screen. I take his point, however, I would question if your work is set in 1950's such as Grease, Lipstick On Your Collar or the Dr. Blake Mysteries, which I was an extra in, then it should mirror the mood of society in the 1950's that I think the aforementioned works did.
I think regardless of time period, if the story is set in a different time period, it still has to reflect in some way on something from today that people relate to. You'll have to make something about the story contemporary.
Grease' mood is completely based around the 80s. It has the cheesy feelgood glam of the 80s; centered around a story all about fitting in; one of the most common themes of the 80s mainstream-It's-Hip-to-be-a-Square-culture, within a group that wants to stand out (ala the 80s punk.) I think it very much depends on what your work and it's purpose is what time period it should reflect. A very good case of a story fitting the mood of the era it's set in more than the era it's made in is American Psycho. The book came out in the 90s (the movie in 2000 or so) and it's set during the mid-80s during the economic boom. However, it works well because it uses it's setting to satirize and critique of American capitalism though; a quite ageless topic.
The market for new fiction today is very conservative.Cutting edge and experimental fiction is very hard to get published.Big publishing houses who publish hundreds of books a year know that most of their titles will fail commercially,hoping that just one or two will enter the public consciousness and make a lot of money.5000 copies sold for a literary novel is considered a small success.The market is awash with sub-standard writing in my opinion.Many people can "write",but having a really good story to tell is something else entirely.
I think it depends more on the story, pitch and marketability than being conservative. But for the most part, yes, smaller press is much more likely to publish more inventive writing. You can always get republished though, if you work on gaining traction and have a good marketing plan executed, and it seems like today a lot of major success from good books come from either an original small-press or independent publishing that later gets picked up by a large press.
("...nah, the problem is that only 3% of you humans are still reading books, or ebooks even, the rest of you are elsewhere where a large proportion are here on this internet now, so the question is how one is going to get readers to read one's posts so that they might then switch to one's books from it..." mentioned the goblin, adding "...but the writertypes themselves tend to be very shortsighted towards the internet, their posts lack narration, dialog, substance and style, though don't take my word for it, just turn up upon any writer's forum and observe the posts first hand...")