As we look back on his career arc, we may see Mookie's 2017 as the true aberration in his performance, either due to injury or general offensive malaise. When your *floor* is 5.5 WAR season at 24, you're worth a lot of money.
If this board has a failing (*if* it has a failing), it's that I think we underestimate the development of our own pre-prime guys (Betts, Xander, Beni, Devers) and assume that their true mean is whatever they established in their 21-23 y.o. seasons in the big show. For example, I think prior to this season there was a growing sense that Xander was really a 15-20 HR guy at best and that his 21 home runs at age 23 was somehow his ceiling. I think it's now increasingly clear that he has 30-35 HR upside. This was the scouting report on him as a prospect, but who here felt comfortable saying that at this time last year? It might be recency bias or some sort of inherent conservatism, but it is a trend I noticed.
As for Mookie, it's hard to imagine him ever playing at a higher level, but as someone else put it, my God, what if he gets better?? Given that he's only 25, his *true* talent level may peak in the next 1-3 years, even if his on-field performance isn't significantly better than it is now. Should it be a surprise to any of us if he played *slightly* better in any of the next few years, especially if he's healthy the full year? What would you be willing to bet that he would have 1, 2, 3 or more seasons with a higher WAR than this one (whatever that ends up being)?