We are only a small percentage of Google AdSense publishers. Even if you toss in the noisy crowd over at the Google Help forum, it's still a small percentage of the overall total. Also, the ones who are doing fine are much less likely to show up here (or there) and bitch about it. They just keep on doing. So of course it looks like AdSense is going down the tubes for everyone, because the people who it's going down the tubes for are pretty much all we see.
AdSense isn't a perfect fit for everyone and everything. And maybe it's changed so that it's not a good fit for sites it *was* good for three years ago, I dunno. I have sites I would never (or could never) put AdSense on.
The important thing is to stay flexible so you can adapt. None of us can make a bit of difference in what Google does. We can only make a difference in what we do.