This still bears repeating ...free agency value is not the same as pre-free agency value. Burnes is not currently a free agent, so 10/400 is not an accurate depiction of his current value.
Free agents have maximum leverage. The further you are out from free agency, the more risk that the team takes on. It's why so many people thought we got such a smoking deal on Yelich, when the reality is that Yelich signed a deal with us that was plenty fair and consistent with him being 3 years away from free agency. He was never going to get 10/350 or whatever despite coming off two MVP caliber seasons.
3 years out, a team runs an inherent risk of being on the long-term hook for a player who ends up injured or who simply falls off a cliff performance wise, as we found out with Yelich.