You will find that a higher resistance will increase the power dissipated through the fault given a constant voltage.

No it won't. Power = V(squared)/R (the more appropriate form of the equation for constant volts) so if R is bigger, power goes down in the scenario you describe. You fail to cope with the fact that as you increase R, the current goes down.

The reality is more complex, because you're into impedance matching where maximum power is transferred when source and load impedances are the same, but as I don't know the source impedance of a lighting strike I can't work any numbers.