Max Verstappen is the clear favorite for the remaining races of the season. If Mclaren or Mercedes finish the season without winning a race, it will be the first time since 2007 that a Mercedes powered car has not won a race in a season. My prediction is that they will finish the season empty. Also Mercedes factory team, Mercedes Amg Petronas, has won a race every year since 2012. But that will come to an end if they don't win. It would be a disappointing situation for Mercedes to end the season without a win. A major overhaul of the team seems likely.
For McLaren, the possibility that they will win the remaining races is quite big considering how the McLaren duo perform. But for Mercedes it will be quite difficult for them to win because besides having to fight McLaren, they also have to fight Ferrari, which has recently been quite aggressive in competing with RBR and McLaren.