Let us say 30% of the searchers for "auto insurance" click on Geico's organic search listing. What about the other 70%? Some of them click on other organic search listings, some of them will click only on other paid search listings, some of them will click on a combination of listings (comparing).
It would only make sense for Geico to buy paid search listings as well - to capture SOME of that other 70% that do not click on their organic listing.
Simply, ranking organically and buying keywords will only increase the chance for a potential customer to find your site. And with an industry as competitive as car insurance, if Geico doesn't spend that $90MM to acquire new visitors someone else will.
Also I highly doubt the accuracy of the $90MM figure as Spyfu's database is only an estimate.
Finally let's not forget this article also doubles as a marketing material for Tipping Point Labs, I'm sure they agree they are "expert story-tellers" who completely "understand online content marketing".