If the competitor is Arsenal, maybe Manchester City can take over, but this time the competitors are Liverpool, of course not easy to pursue them and Manchester City really need luck, so far we cannot predict how this season is over what is clear is that Liverpool and Manchester City will pursue each other.
I agree with you because among Liverpool and Arsenal Liverpool is always the most consistent team, not because they have more skills and quality players but there energy and pattern of play is very unique from Arsenal because one of the things I like about Liverpool is that whenever they sees an opportunity they make sure they grab it and never allow any club to take it away from them, so actually at the moment Kelvin de Bruyne return to Manchester City Liverpool knew that the competition will take another dimension so they make sure to put in all possible best so that they will have more points than Manchester City perhaps there consistency is actually paying them, however Manchester City draw against Chelsea gave Liverpool more opportunity to build more points over them.
So perhaps just like you said if it was Arsenal Manchester City would have managed to beat them on the first position because they are not always consistent, however I doubt if they can be able to secure the second position on this premier League season because there performance is that good compare to Liverpool and Manchester City.