[paulgerhardt]

While I understand the spirit of this comment, if you look at the fossil record you’ll see that’s objectively not true.

Roughly half of the shifts in the last 11 evolutionary periods, over the last 500 million years, were caused by changes that occurred in a-few-hours-to-a-few-thousand-years with 75%-90% species lost.

Evolution did not fail to work then.

[jibal]

You are tautologically saying that massive shifts resulted from massive changes, but that doesn't contradict the statement about evolution--which is about far more than such "shifts" (not an aspect of nature but rather changes large enough for humans to perceive)--operating over long time periods. Every single instance of offspring is a "shift" from its progenitors.

Also talking about evolution failing to work is a category mistake--evolution is an ongoing process that is the inevitable result of imperfectly replicating biological mechanisms and there's no "succeed" or "fail" about it.

[fluoridation]

I think GP meant "evolution without catastrophic biodiversity bottlenecks". Of course evolution will "work" as long as a single species survives.