You wont be able to sell the map if mapowner does not exist, do you understand? Let just say, people are being able to sell the map because they are being protect by mapowner system. Its like a law were created for all goods but some bitches rather exploit it for personal benefits.
Manpower system isn't going anywhere and is used to protect your loot from ks, and allows the players to report hackers. Map selling isn't related to the map owner system directly, But more to human nature in wanting to maximize their profit by the end of the service due to the demand for maps. I feel like most people assume some players would just find a map and sell it or just stay there to do god knows what until it sales, but 99% of the map sellers are people who have just finished selling leech on those maps or just trained and decided to sell to make back their pot money. Remember, potion price increased&drops has been decreased. I doubt there are players who hold the map just for the sake of holding it as its very unprofitable. If you don't wish to support it, That's perfectly fine. Do not buy maps, And if you find yourself in a situation where you are training on those "in demand" maps, just leave the channel or give it to a kind stranger. To me, it's quite the same as selling FM spots. Nothing wrong with it really nor it can be regulated.