My opinion is "No one will sell good adsense earning website with Good organic traffic. If you find someone then the someone will be like
1. website with inorganic traffic or less earning
2. highly price with organic traffic or medium earning
High earning ?? why should they sell.. So, spending high amount on buying (good or bad) website is better than make your own website and place 40 - 50 words unique article (each 500 words) then build some niche relevant backlinks. Your website will get real traffic. that's it.
Thanks,
Bart