PP&L has been in arc rated clothing for years. They, like most electric utilities in the US have a strong arc flash program in place. In cotton clothing, this worker would likely have never lived. The right stuff makes a difference but doesn’t always full protect.
The NESC (National Electrical Safety Code) 2007 version requires utilities to do arc flash studies to calculate “reasonable” arc flash energies. Even when this is done the protection isn’t perfect BUT arc rated base wear will prevent MOST fatalities.