The answer to your first question is in the first sentence you quoted. I'm not sure why you bothered asking it. Anyways, the e main points are;
Geelong had no idea of our cap space situation
They couldn't afford to blow us out of the water without making Danger's value known and destroying their parity system.
They traded only because they had to, meaning that we have the opportunity to maximise our outcome.
If $850k would have gotten through as implied by
Pdub , then they could have lodged that for a potential gain of retaining the picks without risk. They didn't.
Ultimately we agree on the factors involved. Where we disagree is whether we could have gotten that extra 1st rounder. You naively consider the deal we got to be the best purely based on the fact that it's what we got. If we walked out with only the first rounder, your argument would be no different. You would not be in here suggesting that we could have gotten their 2nd rounder.