Mike Trout is good. Real good. But this year, BBWAA voters decided he was not as valuable as Mookie Betts. You could make many argument that Trout was indeed better than Betts, but there is also no doubt that Betts DID have a great season.
Trout has been eligible for MVP the past 7 years and he has finished top 2 EVERY YEAR except for his shortened 2017 season when he placed a respectable 4th.
Trout led the league in walks (122), OBP (.460), OPS (1.088), wRC+ (191), and OPS+ (199).