In a lightning strike, electricity doesn't exclusively follow the lightning rod. That's the problem.
The major part of the current will flow through the rod, but a small remainder can and will cross into the house - TV/radio/sat antennae and overhead electric/phone wires are the main culprits here, but belowground cables and water/gas/metal sewer pipes can also serve as a point of ingress.
Normally you're supposed to have proper grounding at each of these ingress points as well as surge protectors, but all it takes is for one of the grounding connections to be a tad bit loose or a SPD being expired due to prior overvoltage events, and suddenly the pipes or whatever can pose a significant enough voltage differential to the rest of the house to kill you.
And if that news isn't bad enough, most people (especially landlords) do not care too much about their electrical and other wiring in the home. Every few years you should re-tighten wire connector screws with a torque wrench to make sure the connections are still up to the spec of the manufacturer, and grounding rods need to be regularly measured as well, particularly after drought periods to make sure they haven't dried out in the time since the last check/construction.
I did a home inspection on my house and really appreciated the insights there - many hazards were identified and it makes doing a rational de-risking exercise possible.
