Back to the topic of the
Natural Limitation to Evolutionary Processes briefly.
I think it can be summed up simply:
All Darwin did was observe microevolution, something known for millennia already, certainly in the practice of domestic breeding which was his model, and extrapolate from it to macroevolution without any evidentiary foundation, just imagination.
That's all he observed in the Galapagos turtles, all he observed in the finches.
Darwin put Natural Selection in the place of human selection or Domestic Selection as the engine to drive Evolution, and failed to appreciate sufficiently that Domestic Selection leads to dead ends, not to open-ended opportunity for change. If he didn't have the genetic knowledge for that, we do have it nowadays: Both in nature and in domestic breeding selection leads to change leads to less ability to change, ultimately to dead ends genetically, often to disease proneness and extinction. Selection eliminates unwanted genetic possibilities in domestic breeding, and in nature it eliminates the genetic possibilities that are not adaptive. That's how the change is brought about. Sometimes the selected form is strong enough anyway, but the ultimate end is weakness.
They haven't yet faced that Natural Selection and all the other forms of selection that operate on populations decreases the capacity for change. It's rudimentary, just look at the extremes of domestic breeding, also look at some of the extremes in nature that have been similarly refined out to the point where they are vulnerable and genetically reduced. But they still act as if these processes somehow promote change, you will still find them defined as "processes of evolution."
If you point out the problem to them, that these processes actually decrease the possibility of change, to try to save it they add in prodigious quantities of Time, which is nothing but a diversion, and Mutation, which is fantasy. Mutation couldn't possibly save it even if mutation were ever beneficial.
To sum up: the more change there is in a population the less change is possible genetically. Evolution defeats evolution.