He remained an opponent until death (at which point continental drift was widely accepted) which is both a testament to the literally unbelievable energy behind seismic activity and the importance of updating your Bayesian priors as you gain new information.
0. https://en.wikipedia.org/wiki/Harold_Jeffreys#Opposition_to_...
The minimum possible Baysian prior is a base rate of "my senses are just not picking up reality and/or my memory is catastrophically compromised and/or I cannot process logic right now due to some reason" which while low is never going to be 0%. There are too many known ways for human brains to fall over. 0% priors are unjustifiable.
> Max Planck, surveying his own career in his Scientific Autobiography, sadly remarked that “a new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.“ -The Structure of Scientific Revolutions
I think in an apples-to-apples comparison, you would need to attach some kind of device to absorb the kinetic energy from the fault.
He calculated that it wasn't economically viable: tons of wattage, but for such brief timespans, that it doesn't actually amount to that much on a comparative scale. The cost of building the collectors and transporting the electricity (from ocean platforms) was much higher than the cost of using other energy sources. Iirc. It wasn't exactly a serious investigation by a team of engineers, but I basically trust his conclusion.
Maybe it will be more attractive in the future after we stop using hydrocarbons?