Although Liverpool didn't play with all their main players, Liverpool still dominated the match. It is very clear if we take a look at the stats. Liverpool made 19 shots, Man City only could make 10 shots. Liverpool also won the ball possession, it means Liverpool midfielders playing better. If Liverpool plays with full of the main players, the result can be different.
I don't know why Klopp put Salah, Gakpo, and Robertson in the bench. I think these 3 players are the main players of Liverpool and contributed much on every match. However, this may be a tactic applied by Klopp. Well, a draw isn't too bad result. Liverpool still has good chance to win the title in this season. The competition is still far from the end.
Salah may be a physical factor that makes him not be dropped into the starting eleven. after participating in the Africa Cup Salah was injured.. Therefore, Jurgen Klopp did not want to push him too hard to play in the big match, as there was a risk of getting injured again if in a highly intense and pressurized game.
The condition of M. Salah, who has just recovered from injury, is not yet completely safe to play. So Klopp promised in an interview that he would play Salah carefully. So it's natural that Salah only played briefly. But there is an important fact about Liverpool that Salah's presence, even if he doesn't play, always seems to have a positive impact on the team. It seems like his friends at Liverpool become more enthusiastic when Salah is there. Salah was injured after playing for the Egyptian national team at the Africa Cup of Nations. But the injury had healed by then. But unfortunately the injury recurred and he received treatment again. And a few weeks ago, Salah was declared recovered, although not yet in his best condition. And similar things also happened to several other Liverpool players. That is why several of Liverpool's mainstay players were not played from the start. but fortunately Liverpool's second tier is no less good than the main players. This is similar to the second tier that Man City has.