Crowns represent real money. KI already gives players up to 40,000 free crowns a year from trivia. Gold is completely worthless. Gold is far too plentiful to be allowed to be traded for crowns. I need to spend/throw away 200k gold at least once a day just to be able to sell gear to clean pack. If they did this, they would lose massive amounts of money. There'd be no reason to ever buy membership or crowns. By making everything free, you'd basically ensure that the game dies.
Would never happen, unless KI increased the gold limit to 999,999,999 or something like that. Then for 10,000,000 gold you could get maybe 25-50 crowns (nontransferable). KI could add a limit by saying a max of 10 transfers a day and could limit non subscribers to 1M gold cap. (Rest could be stored in bank if membership expired).
It is good that you brought up the subject. Most people never post at all. Unanswered questions can lead to resentment. this thread has probably answered many people who, for whatever reason, would never have asked.