I also found it bizarre that your average go-kart track (not to mention aviation) has the presence of mind to safety wire everything but a multi billion dollar utility company didn't
A century ago, when it was designed, they've probably correctly assumed there's no way a safety line, even unloaded, will survive longer than a hook in there. The hook was a robust solution that could easily last a decade or two.
I doubt people back then were expecting this to be left unmaintained for 97 years.
