This King Air (
https://en.wikipedia.org/wiki/2014_Wichita_King_Air_crash) was operated by a guy with > 2800hrs of multi time. It appears that the auto-feather system didn't kick in (or wasn't armed, despite him saying it as part of the pre-takeoff), and he didn't feather the failed engine. So, now he's dead. If this happened in a PC-12, it's very likely he'd still be here.
If a guy with 2800 hours of multi-time flying a King Air didn't perform perfectly, I'm guessing there are other cases with less qualified pilots where something similar has happened.
Yes, twins CAN be safer if flown perfectly. My argument is that the moment after takeoff is a very unforgiving regime. In some cases, the aircraft being single might effectively save your life over it being a twin.