Bit of both

City has struggled with both chemistry and injuries. Nobody else was going to push Liverpool this year. Leicester has had a very good year, but they were never going to hold up. Tottenham changed far too little to ever have a shot - Jose is making them better, but they need far more changes. United has a loooooooong way to go. Chelsea was both in transition and transfer banned in the summer.

It was basically the perfect storm to have Liverpool shatter records if they could remain healthy, which they have.

I do think they are at risk for the CL simply due to match fatigue - it will be to their advantage to clinch the PL title as soon as possible and maybe NOT focus too much on the unbeaten streak. Who knows with Klopp, though - he may be focusing more on that because they won the CL last year.

edit: Oh, and speaking of match fatigue - tired of beating this drum, but the PL and the FA really need to get their shit together when it comes to scheduling and stop the goddamn replays/2nd legs if they're keeping both cup competitions. It's fucking stupid.