How much does it count against a manager's legacy if his teams collapse after a few seasons? Dortmund and now Liverpool; they overperform for a few years and then it all comes crashing down. It's only two clubs, but still. Can't put it all on VVD's injury--as important as he is, it's not as if they're the first team to lose a key player for most of a season. I recall we once had such an injury crisis that we had to field seven defenders against Arsenal. VVD's absence feels more like an excuse than a reason. We once lost Vidic for a similar amount of time and didn't drop seven spots in the league table. His replacement was an inexperienced Jonny Evans, so it's not as though we had a remarkable backup.
Someone on here once posted a pretty good theory. We know that in Klopp's teams (both Dortmund and Liverpool), something like 60% of the players are medicated for asthma. It's not illegal, but it's obvious that they don't actually have asthma. Can't remember what the medicine is called, but it's really rough on your cardiovascular system if you're simultaneously a professional athlete, so players need to be taken off of it for a while every so often. Normally that's done in the summer when they're on break, but if players keep taking the medicine for long enough, they need to be off of it for longer each consecutive season in order to not risk serious health problems. So after a certain number of seasons, the summer break isn't long enough. And during COVID, the season schedule has been completely different and would get in the way of that carefully constructed medical routine.
Couldn't begin to say with any certainty if that's the reason, but the asthma thing is true, and it kind of matches the pattern of Klopp's tenure at Dortmund and Liverpool. He was at Dortmund for longer, but Dortmund weren't at the top when he arrived, and they didn't have an irregular season schedule to interfere with the medical routine. If this is in fact the reason that he's 2 for 2 with regards to his teams crashing and burning after a few seasons at the top, that would be very interesting to look into.
One thing's for sure: their downward spiral this season is not just because of injuries. Plenty of teams face similar injury problems and don't go from one of the best in Europe to absolute trash practically overnight. They weren't crippled by injuries when they lost 7-2 to Aston Villa early on in the season. While the injuries certainly haven't helped, it's clear that their decline is way, way more dramatic than what injuries alone can possibly be responsible for.