The farm system for the Dodgers is quickly rebounding from many graduates to the major leagues and some trades. Keith Law has already declared the Dodgers to have the number one farm system and most other publications have them in the top ten.
The Dodgers cashed in some excellent prospect chips to acquire stars like Mookie Betts, Trea Turner, and Max Scherzer. One of the reasons to have a strong farm system is to make those kinds of moves. However, the primary reason is to have a constant flow of talent coming to the major league level.