In 2020 they will have a lot of commitments that would make it very difficult to fit Harper, Darvish and everybody else already here, into a budget. Maybe, but they also lose Zobrist and possibly Morrow's money, with Lester and Chatwood the year after. 2 years from now you'll also have much more clarity on which of the position players you actually want to pay through arbitration(e.g. trade any/all of Schwarber, Russell, Baez if they don't improve). If they go that route you're also likely keeping Almora and Happ around, which furthers your flexibility in those years. I'd love the books as clean as possible for 2021 when we likely are going to have some big deals along with hopefully Harper already on the books. I really like all these two and three year contracts they are signing guys to. The Cubs core is already good enough to win the World Series during this window, so I'd rather not make huge, long-term commitments unless they are truly elite guys who also are still young.