If you think the team will be garbage in three years, it doesn't matter if they sign guys or not. I'm not really understanding your argument, frankly.....We all agree, they need at least 2 of their minor league pitchers to be good to great. No one is arguing that.
the question is....should they sign 1-2 FA starters? I vote yes, on at least one. The young guys need mentors. They need someone to even just watch how they do their job, how they prepare, everything. Also, if 2 work out, and you've already signed a guy, bonus! If none work out, it doesn't matte if you sign a guy or not.
There is little downside to signing one good FA pitcher. They have the money, they need 8 pitchers and have 1 or 2 right now....I don't see the downside at all. If the young guys are good by 2023, you have a guy locked in. If the young guys are bad, you can trade him (or not, if he's not working out). If somehow too many young guys are good, you deal someone for some f'n defense (which this team utterly lacks).