At this level though isn't that the point, trying to eek out every last bit of performance. If that's not the goal why make something like the Model T's in the 1st place as the lesser models get the job done just fine or even more extreme, when something like Bose gets the job done

Can things go to far, sure because I highly doubt items like $200,000 speakers actually have anywhere near that amount of $$ worth of parts into them, a huge chunk is markup, even when factoring in R&D costs so "snake oil" isn't limited to cables. There's some solid science that goes into different aspects of cables from different manufactures but whether that yields any actual audible improvements can be argued to the cows come home hence the long used snake oil counter argument.