>I’ve never imagined link farms to be so profitable an enterprise that they could afford a team of phds and come out ahead; but if they could, then its an arm race, and google would be at a much greater disadvantaged if they didn’t have their own.

Go on a blackhat SEO forum. Look at the number of sellers, the number of listings, the number of positive feedback and the cost of some packages (you can easily go on and spend 50$ or a 1000$+ for a single package). There's a LOT of money in blackhat SEO. That's just the people offering to do it for you.

Then look at the dozens of software packages for sell that are constantly being updated and have both one-time fees and ongoing subscription pricing.

Then go look at the people selling just various social media accounts which mass-creation of gets harder and harder.

Then there's people that sell VPS access. They'll buy the software tools and host them all on a VPS and rent to you weekly or monthly so you can shell out tens of dollars or hundreds of dollars a month instead of needing to cough up thousands just to get all of the software for the month.

And that's just what's readily available with paypal or a credit card on the clearnet.