Yes. But that does not explain what would happen after a single write to each existing block was performed. The clean list would be exhausted and the trash list would be empty. Then what? Yes, there might be some 1-5% extra physical blocks reserved, but they still won't do good - basically, the wear leveling would only be done in that small zone, which would get exhausted really fast and it is not what wear leveling is supposed to be.
I am personally inclined to think that the whole FTL thing is a hoax. It might work in some cases (e.g. you have one file on your FAT filesystem and you constantly overwrite it), but in general I don't see how it could work. Once you fill all your flash with files completely, there doesn't seem to be a way to perform any real wear leveling any more. You can erase all the files -- it won't help, the underlying device would never knew you did, it's a logical operation which doesn't get propagated down to it. For it, all the space continues to be filled up. Not much it seems to be able to do then.
So when our editor writes that "an SSD will end up shuffling around data that the host system has long since stopped caring about", I don't understand just how an SSD would do that at all. Seems that everyone is just happy to believe that it can be done somehow, because the marketing suggests so.