I find this is part of the changing demands of the market. If they want to cater at all to the new wave of lightweight hikers, they NEED to post their weights. Unfortunately, we are still quite a small minority and I think they prob don't see making a ton of money of this crowd (us). As someone who works with the general public and products, there is a change in the way people think. More and more people are accepting the idea of lowering pack weight to more easily enjoy their time outdoors and they are willing to pay for it.
I have noticed more companies starting to clearly list weights of their products. Eastern Mountain Sports is even starting to do that. (I first noticed with the EMS storm front rain jacket (full featured 3 layer pit zips etc for 10.7oz).
Sea-to-Summit is very good about posting product weight clearly on the actual product packaging in store. Great for us consumers who forget to bring our nerdy scales with us.