"In your opinion, what are the possible reasons that explain why Larian decided to go for their policy of nearly non-existent communication ?"
I think this is because two-way communication is a double-edged sword these days. Interaction directly with the developers can be distracting, time consuming, frustrating, and sometimes hurtful. People will type things that they would probably never say in a face-to-face talk. We've all seen this, not just here but everywhere.
But at the same time, there is a spirit of community that has always been an integral part of the D&D universe. In my case, I played table-top D&D a little bit but never had much of a local community to play with. So when BioWare came out with BG I, I was excited to see what a high level character (7 or 8) could do. In my first play, my mage got immediately killed by a wolf and I almost walked away. I am not patient with games. But, for some reason I ended up making up an account on the forums and found tons of helpful people there giving advice, reporting bugs, telling funny stories, etc. I got some tips and good laughs, and I have enjoyed the game ever since. And I started to notice some of the BioWare people were actually participating in the discussions. Wow! I was communicating with the people who actually created this great game! And sometimes they even responded to my questions or suggestions. I will always be grateful to the BioWare crew for being so active as real humans on the boards, as that made me feel more a part of their game world. I suspect Larian has the same kind of people that I would enjoy talking to, and we have very good Moderators here, too. But at the same time, I respect Larian's decision not to stick their hands into the "tar baby" that is the internet these days.
