It's funny how different MAs act differently in different places. I've cultivated a relationship with my MA (she has become a friend) and she always shows me her update book. Often I tell her about upcoming collections before she goes to update - she knows I'm on Spektra and thinks it's cool that sometimes I know more than they do. She always puts collections aside for me to decide what I want, so I consider myself very lucky indeed. I rarely miss out on anything.
I went to Macy's near me this past weekend to get a backup of Band of Roses - the MA was very nice, and I happened to mention that I am excited for upcoming collections - she agreed, and then pulled out the update book of one of her coworkers (she said she was going to update this week) and we browsed through it together. She was happy to share what she knows, and what is upcoming.
Sometimes I think when they don't want to share info it's because they know you're not necessarily going to buy 'what's currently on the truck'. They'll have to wait for your purchase like you have to wait for your product: no current benefit. If they're trying to meet a goal for a month, and the launch isn't within that month, it's not worth their time. I'm not saying it's right or wrong, just may be an explanation for the behavior. In my opinion it's quite short-sighted, but there it is.
It's very difficult to find good MAs that are there for the long haul, and open to relationship development. But it also boils down to customer service - and many of us have had bad experience lately.