This is not true, at least a$10 and $50 Chianti is very easy to taste the difference since the more expensive is stored longer and much 'easier' to drink.
Usually the difference from $50 to $150+ has a lot to do with aging too. You're essentially paying someone to store a high priced item for you for [x] years in appropriate conditions. Depending on your tastes and the wine it can be a huge difference whether or not its worth it.
There are also some pretty big differences in agricultural techniques applied to different wineries. The first growth Bordeaux guys are employing experienced growers at the top of their fields to consider things like harvest time, planting conditions, soil maintenance, etc., these costs do get passed along.
I'm not sure about a $50 and a $150.