Interesting. I learned many years ago from Andy MacPhail that pitching is a numbers game. Falvey has shown himself to be pretty adept at accumulating top pitching prospects. I'm guessing our scouts are on the same page as Wes Johnson. It appears few teams even try to take care of their starting pitching needs internally. Cleveland, Atlanta, San Diego and possibly the Dodgers come to mind.
Never is a long time. My guess is no later than 2023, possibly 2022, most of our starting pitching needs will be taken care of internally, just as we have relievers. It should be noted, most teams won't even try.
If you have 2 players of equal ability, take the younger one. That said, Chacin will be picked up, if not bid on. Too many teams desperate for starting pitchers.
We will have internal replacements for Berrios prior to 2022. No need to break the bank or pick up a Mauer contract in free agency. We can take care of our bullpen needs internally.
Chacin still has time. I would guess rival scouts are watching. There are a number of desperate teams out there. The Red Sox and Angels come to mind. If you follow MLBTR you'll see it changes almost daily.