The pitching prospect is only about to enter his third professional season so I really don't get why people would be so anxious to flush his potential future value down the toilet for a rental player. He was averaging closer to 5 innings per start towards the end of the season after being built up. Some pundits believe him to be the most talented left handed starter in the minor leagues and he's been given a 65 FV by Baseball America. Excuse me if I think it would be an astronomically bad move to trade him for a 1 year rental player, no matter how good that player is.
The team would have no chance to extend Soto before he reached free agency. The Yankees knew this and basically didn't bother trying. The team would be stuck bidding against the rest of MLB for Soto's long term services, and not having him for this season allows them to take a crack at it next offseason and keep their best prospect. The comp pick more than likely would end up being nothing given where it's located (after second or third round if memory serves). Given how difficult it's been for the organization to develop their own starters it's total insanity to even consider trading the guy with the highest ceiling of anyone in the entire organization. The expensive rotation is quickly becoming unsustainable with the looming Vlad and Bo decisions, and it's as expensive as it is due to primarily building the rotation through free agency and not internally.