The amiga scene is far from dead. Clearly there is less releases than before but there are plenty of reasons for that. One thing being that most people active on amiga have been so for a good long while, they have released quite a few productions and are therefore not interested in releasing something if they aren't happy with it, releasing something just for the sake of having a production isn't worth it anymore. Secondly, the expectations from the scene has risen enourmously over just the last 5-6 years, Amiga demos now are expected to have a ridicoulous amount of content, people aren't interested in simpler demos any more. Just look at recent TBL/Nature/Elude stuff, doing all that 8-bit,shadetable,... content is a huge effort. So it's not just that we had more time when we were 15, making a demo of 2009 quality takes a lot more time. I find it kinda weird but to me the Amiga has somehowe become the most graphics driven platform of all. Of course there is also a lack of coders but that has been the case for a long good while.
However, there couldn't be a better time to enter the scene for people here who are interested. It isn't that hard to get started and one good thing about the amiga scene compared to any other scene is that there isn't much elitism around these days and people are really very helpful.