I think they can sill realistically challenge but only if they have a fit squad for most of the year. They look very top heavy now. It is crazy to see the list of players that have gone out the door in the last few years - and especially last year.
Also going to Vegas probably had a negative impact. They already had a shorter time off due to playing in the last game of the year, international games, and then they are in Vegas in late Feb playing for points on the 2nd of March. They played great but it would've taken a big toll on recovery with flying, jet lag, etc. They then play in a lung buster with a fired up Roosters team and then Melbourne away. They played awesome but it took its toll as they were not there in the 1st half last night. I think they would've been behind at half time no matter who they were playing.
In hindsight Talagi should've started never mind not even getting a bench spot. That's a weird one. I'm assuming he was dropped and not injured? Also should've kept Jenkins at FB, Alamoti in the centres, and Laurie on the wing. All hindsight of course.