We have a client right now who is in the real estate sector; they ran ads leading people to a free guide which itself eventually leads them to the clients sales

We have a client right now who is in the real estate sector; they ran ads leading people to a free guide which itself eventually leads them to the clients sales people. They had a home sell on the first couple of thousand of FB adspend (~10 days) and this way outperformed adsense. YMMV for all of this stuff; I have often thought the same as this author with respect to adsense and other PPC. What isn't figured into "many, many people who have" is their ability to make decent PPC ads, landing pages and other creative solutions to making clicks work for them...