Acuna had like 3.3 bWAR at the 81 game mark of his career. Half a season. His trajectory puts him squarely on course to exceed that in his prime years. By a lot. But even if he doesn't, I think 3 WAR is on the absolute floor of what you could expect of a prime aged healthy Acuna. Of course there is injury downside. But yeah if the worst realistic non-injury scenario for Acuna is paying him market value, while the upside is him being one of the top 5 players in baseball, you bet your a** I would pay him 25 million a year 6 years from now.
What is your argument here? Is it that we should let him walk no matter what? Is it that we need more data? Because if we spend 3 more seasons getting data on Acuna so we are 100% sure that he is going to be a stud in his prime years, it'll be too late. We'll have to either pay him upwards of 40 million a year (while also guaranteeing him a contract that extends wayyyyy beyond his age 30 season) or watch him walk after arbitration. The downside to both of those are not only likely, but inevitable. We would either being paying an absurd amount of money for a declining 36 year old in 16 years or he'll be a Yankee/Dodger/Red Sock/Cub in 6 years.