An article was doing the rounds in Sept 2020 whereby it stated 22 of the 35 players in Liverpool's squad had asthma which is 63% (more than 5 times the national average). It went into details of dodgy docs around the continent and "doping". I put that in inverted commas because the substances involved are performance enhancing but legal to treat asthma. See Bradley Wiggins for more details. It talked about caffeine and other boosters to give energy levels a lift but talked about the clear risk to player's cardiovascular health from continued abuse from medical supplements and suggested a Liverpool decline was predictable because they'd had to push so hard.
With their efforts this season if they do drop off next year, we'll know why! But then they've built an amazing squad and can challenge on more fronts in any case.
I'm not sure how much I buy it. They're an excellent team, Klopp does use his key players more than Pep but perhaps they train for that style more and they've just had some luck with injuries. Who knows. We've challenged for all four trophies before, it is possible. We lost to Lyon in the CL when we should have been beating them comfortably. Playing Inter, Benfica and Villareal to make the CL final certainly helps their cause. Things have just fallen into place for them as a result, particularly with our need to rest players in the FA Cup semi where they did that in the CL instead.