Serie A is indeed a joke these days. Just look at Juve's game against Fiorentina. In a game that they should've been trailing 6-0 before the 30th minute, they end up winning 2-1 because their opponent lacks quality. This is the kind of opposition Juve faces every week and then when it comes to Champions League, a determined Ajax can easily exploit their complacency.
Same goes for a team like PSG.
What's funny about Juventus is, despite all the stars and the relaxed league campaign, they can't put on a decent free-flowing display of football. They play a very crappy style of football that heavily relies on the odd shot or cross from one of the superstars upfront. Not impressed.