Concerning your discussion on what are the important criteria for search phrases, I think that from whichever angle people approach the suttas, they will always end up with the way to the end of suffering. Simply because this is what the Buddha taught; he didn’t teach anything else. The whole mass of suttas are all an elaboration on the four noble truths, aren’t they?
Whether people are asking a question directly associated with their suffering, or they look for something inspiring, or whether they are just curious about how a certain concept developed over time, like this, their search will always lead them to the only thing the Buddha ever spoke about: suffering and the ending of suffering!