They're here to stay. The only luck they enjoyed this season is that none of their most crucial players suffered a long-term injury. Their main issue is the lack of depth in certain areas. Their supposed "luck" is a nonsensical argument in my eyes. When you can turn up the volume, pin your opponent down and fill the opposition box with 7-8 players, you force mistakes. We did that plenty of times under Ferguson. One could also argue that City were lucky too because they scored with their first attempt on target in a string of league games (late in the season when the intensity of their performances has dipped a bit) and this gave them the opportunity to control the game better and find more spaces. But when your attacking options are as good as City's, this can be expected. We did that too under Ferguson.
Unless one of Mane and Salah is lured by bigger wages and (hopefully) fecks off to Spain, i can see them going toe to toe with City next season again. But then again, it will not be the first time they will lose a key player under these circumstances. They coped because they listen to the manager's demands and their scouts are doing a good job (knowing that the highest earners cannot be afforded). Might not be next season but they will find a way to be competitive again.
I was watching the game yesterday and i was thinking this: Their attacking trident can provide them with 65-70 goals p/s (all comps), their FBs can add 20 assists (or more), they know how to score from set-pieces. Just imagine if they could unearth a KdB kind of midfielder with their scouting, one who would fit right in Klopp's midfield but also give them 20-30 goals/assists from the central channels. Their first xi would be unstoppable, simple as. Their main problem under Klopp was that they couldn't keep their intensity in the second half of their seasons. They seem to have found a solution this season.