**"Seattle trades for Nelson, the 49ers trade for Buckner. Why are sitting here doing nothing? It's a fair question. Even if the answer is 'Well we don't want to give up draft assets.' Why not? Do you honestly believe those draft picks will pan out better than Nelson or Buckner? Of course not. Is it a finances thing? We don't pay a QB anymore, we have cap space for moves exactly like this. Why should we have any faith in this team?"**
OK. I get it, people see the big name and the relatively reasonable trade package and want to know what's up. It is a fair question. Not sure you'll appreciate the fair answer, but let's try anyway.
In both the Nelson and Buckner cases, they are in the final year of their contracts. So the picks they fetch were always going to be less because they are rentals. (I noticed you didn't bring up Jeffery Simmons, because he cost 2 1s, but he is way younger and under contract.) Both Buckner and Nelson are on the wrong side of 30 too. Doesn't mean they can't keep playing, but for how long? And for how much?
Much bigger to me is that in both cases, a) the player isn't going to be happy going to a non-contender and b) the teams, especially the Colts with Nelson, were going to want to do right by their player. You could trade for Nelson, but he's not going to want to re-sign. If the Cardinals wanted to trade Budda, for instance, they aren't sending him to the Saints or Commanders.
Those are moves you make when you are closer. Not when you are -- at the time -- 2-5.
P.S. They are paying a quarterback. He just happens to be playing for a different team. Not ideal, but the truth.