My amateur opinion about the drop in Liverpool goal scoring:
1. Opponents realize that they must be real physical with Salah, and show him early that he's not in a "civilized" pick-up game. He's stronger than he looks but he doesn't like the banging at all.
2. Klopp knows this and has changed the attack. Lots of times Salah is low middle almost like what you guys call a "9" position (obviously way closer to a Chicharito --- a "Fox in the Box" --- than a Lewandowski) , but Liverpool doesn't use that well. Salah might be free enough to not get mugged wide right, but this often gets BobbyF out of the attack --- BIG mistake. It also seems sometimes to crimp Mane's style. Mane needs to run at you with some wide space and have Robertson crashing wide as well.
3. But I think the main deficit to me has been the way the midfield is working. No matter how good (generally speaking) Keita and Fabinho are (and they are very good soccer players), their presence in lineups cancels the effect of the Klopp Uber-Press. Henderson, Wynaldum, and Milner were just made for this half-crazy/wild in-your-shorts midfield terrorism. Without them maniacally blasting around, there are less and less dangerous turnovers by opponents which find the fab-three suddenly down the goalie's throat.
Klopp is a genius, and he obviously has a great plan. As a coach he thinks that guys like Fabinho should make Liverpool almost impossible to score on (if Henderson is in there too.) If the other guys have "0", all you need is "1". But getting even one (often by things like Salah fouled in the box even) is hard to come by. With a crazyman like Becker in goal, you never know when one of his mystery passes is going to put you behind.
Salah is obviously also not playing as Klopp would like him to, and Klopp preferentially pulled him the other day, and with very little interaction (unlike Klopp) as Salah went to the bench.
Liverpool is full of outstanding players, and they are mainly geared for a 21st century game of all-field lightning bolt running. Salah. Firminho, Mane, Robertson, Alexander-Arnold, Milner, Wynaldum, Henderson --- workrate warriors. You can't throw other pieces with different attitudes in that mix without dumbing it down.
