Being young (24), I can say that in my experience and opinion, the hobby is still how you first described it. I wouldn't be where I am in the hobby, knowing the things I know if other people weren't willing to share experience, knowledge and ideas.
I would say that the only thing that has changed is that the internet and electronic communications has made it much easier for any loud mouth with a big ego to self promote. In any hobby/group of people, there are always the loudmouths/nasty people, but they are also small in number and not representative of the group/hobby as a whole. I don't think that the number of them is increasing, they are just a lot more visible than they used to be.
The flip side to that coin is that it is also a lot easier for those people still willing to help and share (and there are a lot) to do just that. look at the Altamont forums. A few nasty, loudmouth people, and sometimes things get pretty nasty, but overall, lots of good information and genuinely nice people that just want to gather and share information.
Matt
Moscow ID