If they don't resign any of their top young players to extensions, they likely will have a 4-5 year window of being competitive still before they all become FA's.
This year with everything clicking, they should have added more at the deadline, especially another top starter. They should have went after Verlander or Mad Max at least. Things from year-to-year can change in baseball. Players regress, get injured and miss significant time etc. Need to take advantage now, not 3-4 years down the road when these guys will almost be FAs.