Few people are interested in devoting a week of their life to try and figure out which product or service is the best available. Even spending that amount of time wouldn't guarantee that they chose the very best.
Most people are just looking for a very good, safe choice. That's where the value of a brand comes in.
Those buyers who choose Sony products probably buy them not because they're convinced that they're the best that money can buy, but because they're an excellent, safe and easy choice.