Because it benefits the owners financially and they are using it as a bargaining position to get what they want. You also have former international signees who want the system to stay because it brings a lot of money to their country and communities regardless of how well those players perform. These 16 year olds get their bonus straight up which means more people benefit within their country. A draft will suppress that influx of cash and put a cap on earnings for the vast majority since it will have hard slotted bonuses. The top prospects will still get their millions, but those players towards the middle and bottom will be phased out of their life changing money comparatively. A 16 year old with a $100k bonus has changed the trajectory of their whole family in the Dominican Republic, et al whereas MLB teams throw that around pretty easily to hopefully hit on a gem. A draft will limit that for the vast majority of players. I guess I don't know where the draft slots would fall, but only seven of the players the Brewers signed in the most recent signing period got $100,000 or more. Most got $10,000. In contrast, only one of the draft picks the Brewers signed out of I believe 14 or 15 got less than $100,000. At the end of the day it's a complicated and significant change, not something you want to be considering at the last second. Plus there were strong objections (or at least strong concerns) from many Dominican players. It's a shame because it looked like we might have been able to get a deal prior to this becoming the big point of contention.