I understand this. What I don't understand is where the problem is. Life is not infinitely plastic, and evolution does not always occur at rates sufficient to prevent extinction.
Evolution is, in effect, a problem solving strategy, a game strategy. It doesn't win every deal.
I realise that. I don't see the problem with the explaning extinction as much as I see problems explaining why any life is left at all. Sheer numbers help, to be sure, but considering how easily a species can be wiped out by climate change or disease, I think that the harder issue to explain is why it wasn't all wiped out. Mutations would have had to occur often enough, at the right time, and in just the right way to allow for adaptation to the conditions that ended up occurring. It seems that there are too many variables that have to work out together at just the right time in the right way.