I think its also just really hard for people to quantify on a small scale. Its much easier to reason about whether or not you get, on average, $25 a month worth of value from a subscription to the New York Times than it is to try and guess whether someone's review of a vacuum you're considering is worth $2 to you or $0.37 or anything in between.

Or if the stakes are even lower and you're not avoiding a lemon of a vacuum, you're getting marginal improvement to an experience - what is it worth to read someone saying "don't go to Jim's Ale House when on vacation there, its fine but Jacks' is nearby and better"? Clearly that information has some value, but... how much? Whats the cost of a tip that helps turn a serviceable meal on a vacation into a better one?

It's also subjective down to the individual, so how would you even quantify it properly?