As FingerMoon said, the reason he was over looked is in the 3 year period, from start of 2015 to end of 2017 he had 4 wins and 5 losses.
That clearly looks really bad.
But when you look closer at those losses, 4 of them are split decisions.
First, he lost to Laquinta. But that was one of the worst robbery i've ever seen. Masvidal was toying with laquinta. MMAdecisions was 90% in favor of masvidal.
Then he lost to Henderson. This was way less controversial but it was a close fight.
His fight to larkin could have been really different if it was a 5 rounder. Masvidal was killing it in third room. He took too long to start fightning.
His fight vs Maia is interesting in the sense 2 judges gave it to masvidal for round 1, and 2 judges ALSO gave it to masvidal in round 2. So it could easily have ended up being a win for masvidal.
Overall i feel like old Masvidal was kinda taking it too easy and was happy getting boring decisions if he thought he won. New one is much more agressive and stopped trusting judges.