>Think about it: Every business, from tiny boutiques to online giants like Amazon, tell you exactly how much each of their items costs. Why shouldn't it be the same when we're shopping for a job?

That's backwards. The employer is shopping for the candidate, not the other way around. You are the product and they are the one handing over whatever your price is in cash. That's why they ask how much you cost ("what's your salary expectation?") It's the product, the candidate, that typically dodges this transparency.