If you wait the price can come down and you gain more leverage as teams come off the board. Maybe the price doesn't come down, but as long as you're not desperate or can still pivot there's little risk. I can't name a time when Jed had a bad offseason because he waited to long, he usually ends up with good players on good contracts.
Had we paid Bellinger/Boras what they wanted in December two offseasons ago we'd have paid out the ying-yang. Montgomery and Chapman were also steals that offseason, and Bregman didn't get the longterm deal he probably wanted last year. Maybe it's mostly a tactic that works with Boras LOL.