https://www.gregmat.com/problems/verbal?problem=wily-negotiators-proffer
Why isn’t the answer suitable? How do we understand that the blank has to be filled with that far?
Because “suitable” doesn’t explain why the other side “will not quite go that far.” The negotiator deliberately starts with a deal that asks for more than they expect the other side to accept, knowing they can settle for something less but still favorable.
This is what the sentence says:
A cunning negotiator will offer ________ deals because he/she knows that although the other person on the negotiation table will not agree, they can both agree on something slightly less than that, but more favorable for the cunning negotiator.
It is like the famous quote:
“Shoot for the moon. Even if you miss, you’ll land among the stars”
This quote is scientifically incorrect but it carries the same idea expressed in the question. ie
Aim beyond what you can achieve. You may fall short, but at least, you’ll be closer to your “unrealistic” goal.