Reasons why someone would sell a system?
1.) Getting an amount of money for it that is currently considered a large amount by the seller.
2.) Scam.
3.) Can't think of any other reasons.
For myself it is number one, I consider $200,000 a large sum of money, therefore I would sell the program I developed for that amount. Of course eventually as my portfolio multiply's I would never sell it at any price.
Tired of trading is a weak reason, how can you be tired of trading profitably?