- it is of vital highest priority for Google to stay ahead of SEO spammers, or they may stand to lose their $$$ billion search business. So resources to fight spam will always be allocated
- it would take only 1 smart Google person to write smart algo, and it will get amplified by 100,000 server cores at Google. And Google employs >> 1 smart EE
- the Chrome browser has 50% market share and may collect enormous SERP quality / engagement metrics on what "end users" actually click in search results, how much time they spend there vs amount of content on that page, and what page finishes each search quest (i.e. user has found what they were looking for) - these are in fact one of the best "quality signals" available to Google.
- and Google could completely ignore signals from any Chrome instance that has even slightest suspect on being manipulated (Chrome is a native app so it could monitor mouse movement patterns, etc).
- I would say Google is much better equipped than spammers to keep staying ahead. Of course, there are going to be some short term advances in a black hat SEO or social networks manipulations, but eventually every serious loophole would get closed
So yes, Google does work to stay ahead of SEO spammers by providing a better service than them for those who are willing to pay, because the consumers don't care and as long as you don't get Viagra commercial and 17 types of malware by clicking on a promoted search result in Google neither will you.
But it's a dynamic and adversarial environment: the corpus evolves to destroy the quality of search results (spam/SEO). A 20-yo version of Google will be way worse than Google was 20 years ago, because when it goes live it'll be attacked by 19 years of spam innovation (if I can use that word in this context).