2. You can only really judge a player after his career.
that's factually wrong with so many stats being recorded since more than a decade. for a quick and dirty example you could easily tell within 2 minutes if there was any player in the top5 leagues who averaged 5 tackles per game and could score 10 goals during a full season like vidal was capable of. and there's zero players like him. you can also compare full teams or let's say a complete midfield based on their performances.
of course stats aren't everything, they ignore mentality, leadership, off the ball movements and many non quantifiable things, they still provide a useful baseline for similar comparisons. you know whether an in form de ligt was comparable to top chiellini. you know for a fact how van dijk's performance dropped throughout the last few seasons and how he never matched barzagli's consistency over almost a decade. and if there was a barzagli in the making hiding somewhere, giuntoli (and everyone with a brain and an opta subscription) would be aware of him.
athleticism is on a different level, i agree. skill though... i watched a bit of a random pl game the other day, and while they ran like madmen indeed, they were shit with the ball and it wasn't even funny. many countries find difficulties in selecting enough talent, because young rich west european dudes care more about playstation and fashion than playing sports. that's a real problem agnelli repeated many times and if you look at the state of the italian nt's you'll agree. there are individual counter examples, scalvini or baldanzi are bloody talented, the fact still remains: with every passing year, less guys want to be pro footballers
anyway, i like to be wrong on my pessimistic views, so as always, i hope that we'll see a juventus with more quality than the 2015 team in the next decade. if there are so many talents and the general level of players gets better with every year, then it's not impossible