Well, he also said that the ad content also has to match the platform, and that can be very time dependant --- what didn't work 3 months ago might work now, and

Well, he also said that the ad content also has to match the platform, and that can be very time dependant --- what didn't work 3 months ago might work now, and vice versa. So that argues for a huge number of iterative experiment, measurement, and adjust cycles, which is why the essay argues for a lot of automation since to be successful you need to do this a lot.