"The takeaway here is obvious: Keep training people not to click those phishing links!"
Obvious, but also obviously NOT ENOUGH. You can reduce the incidence of your staff being phished, but you *cannot* totally eliminate it. Therefore, you cannot responsibly base your cybersecurity strategy on that assumption.
For those few of us readers who may not already understand that point, defense in depth and robust intrusion detection and response are essential.
Also essential, if perhaps a tad less obvious, is NOT shaming the phished victims into hiding the fact. That just helps the bad guys. Establish an infosec culture of *immediately* contacting Security, and of Security responding immediately in a supportive manner. No blaming, no shaming. THAT way you get the fastest possible notification that you've been attacked, and you stand the best chance of minimizing the damage.
Sure, you may get some false positives this way, but that is far outweighed by the benefit of quick and effective detection.
OK, so you MAY need to shame some C suite idiots into being more careful and more forthcoming, but that's a tool to be used sparingly and with great care.