Bad installers snip off wires so they don't have to connect them!!
A ground wire on a device, does nothing for lightning, but provides a path to
ground to blow / "clear" the fuse so the faulty device no longer has power on it.
These transformers usually make 24V AC, but measure lower depending on the meter you use (AC true RMS,
AC average responding or just crummy!)
In your case, it's likely the chine faulted and melted and took out the transformer, they often
have a small thermal link inside the transformer winding.
If you're next transformer has a green wire, ground it, they provided a wire since the metal
core of the transformer is not connected to the outside housing, a 2 wire transformer will
have the core bonded to the housing per UL and CSA certification rules.