I'd like to get actual confirmation of this, but my vague feeling is that, once upon a time, Google Search would get "updates", as in, actually deployed code that would change the rule of the game and most of the previous dirty tricks would become unusable, leading to people to go out and find out new ones.

This changed with the Google "machine learning" days, where you no longer have humans at the helm laying down explicit rules, so no more "change the world" updates, you can only slightly nudge the parameters towards what you want, meaning the same old tricks keep being effective for far too long.