Those moves all worked out, but they were more cut and dry - the arguments for letting them walk were pretty easy to see. And we had internal candidates ready to go immediately. Zimmermann leaves, fine, we can find another solid SP. Desmond - we had Turner. Harper? Soto & Robles.
Your point about 3Bs aging poorly isn't wrong. I guess I'm just not looking for a bargain and more looking for break-even if we can. I also think Rendon's bat ages more like Beltre than any of those other guys. He's patient and disciplined enough and gap-focused to (IMO) decline into a .800 OPS line-drive 3B or 1B.