You have the right idea, and I believe it is called the Lemon effect or something like that. The market has a degree of variance for prices, usually the better bikes rise to the top, and the crappier ones go to the bottom because they know they can´t get the same high price.
Also, some people are just idiots and price their stuff way too high. I bought an 05 R6 for 3300 - STEAL!!! and it was in beautiful shape minus usual wear and tear. sometime you get a good deal, other times you get screwed. make sure you give the bike an 100% inspection before giving cash.