I wasn't even expecting Liverpool to slow down because Salah left. Klopp knows how to handle his team well. The year Liverpool won the League last, both Salah and Mane left for the AFCON, and still Liverpool held on. It's just for a month at most and about 5 league matches would be played within that time.
Even with Salah injured, I don't think that would do so much to Liverpool.
I'm not surprised if Liverpool performance will be decreasing without Salah. But Klopp proved that they still could win the match with big scores without Salah. In the match against Bournemouth, they could win with 4 goals. They played without Salah, they have no problem to beat Bournemouth. However, I'm not sure they will be easy to score goals if Liverpool played against a strong team with solid defense. They actually still needs Salah for the big match.
What would decide the league winner IMO will be the matches between the top teams. Arsenal, Manchester City and Liverpool still have to face each other. If Liverpool can get 9 points from these two fixtures they will be so close to winning the leagues. If Manchester gets the 9 points they will win the league IMO. At this point in the league, I don't think either of these teams will drop unnecessary points along the way, injury or no injuries.
In the next 2 matches, it will be crucial matches. Liverpool will play against Chelsea and Arsenal. Sure, Liverpool will be safe to lead the EPL standings if they could win those 2 matches. I have no doubt that Liverpool can beat Chelsea, specifically the match will be at Liverpool home. But it won't be easy for the match against Arsenal, it will be away match. Moreover, Arsenal must play all out to get points. There is a chance for a draw in the match against Arsenal. So, I'm not really sure that Liverpool will secure 9 points in the next few matches.