It not hard to see why management would assume the team won't compete in 2022. But why make moves that make it impossible to compete in 2023? The likelihood is that they won't compete in 2023, but why concede that now?
Yes. You build a good team once player at a time. If you are set with a good catcher for a while, that's one fewer spot you need to solve. IMO, you want to have enough spots filled so that outside FA's can figure that by adding them in, if they play well the team has a chance to be good. Build it one player at a time, and Contreras can certainly be one of those.
Still, bad-value contracts have consequences, and limit future options.
reb, you're certainly right, that players aren't consistent and that Contreras had a much better year in 2019 than in 2018 before or 2020 or 2021 after. So, if you want to give him a contract at a price that assumes he'd frame like 2020-21 and hit like 2019, that's fine, and may prove wise.
And you may be proven very wise to have done so. But there's certainly a real possibility that over his next contract, that he'll maybe hit more like the 2017-2018 versions of Heyward (.715, .731 OPS), than like Willson's 2019 season. It's just the risk you take.
I'm not very concerned about risking what might turn out to be an inflated contract. Who else is going to take the Cubs money, until they build up enough of a skeleton that a good pricey FA thinks he can join it and enable it to contend? So offering a bad contract, or what proves to become a bad contract, might be totally acceptable.