This topic seems to have gone off-topic at somewhere the vicinity of message 4, or is it part way through message 1? That said, I still reply.
Finding out what doesn't work is very nearly as important as finding out what does work. Some things work for a while and then they don't. Perhaps all of these failed life forms were merely stepping stones on the way to some ultimate objective. Perhaps the variety is the objective.
No.. Evolution is not an entity trying to find a path or what works. All that is required for an evolutionary direction, is for a group to survive and pass on their genes. The ones who do not reproduce are dead ends and populations that go extinct are the ultimate dead end. No objective, nothing to do with variety, not a stepping stone, just a dead end.
...populations that go extinct are the ultimate dead end.
It seems to me that a population can go extinct via evolution. They reproduced and evolved into a new species, or perhaps a vast chain of new species. The original species no longer exists (is extinct), but was not a dead end.