How was Barcelona the favourite for the Champions League last season. There can never be only one favourite for it. If you had said, Barcelona were one of the favourites then it's very valid. Liverpool was seen as one of the favourites but exited earlier in the competition. PSG was one of the favourites as well, same as Bayern Munich too. All I'm saying is that, there cannot be only one favourite, there's always two or more favourites to win a competition.
UEFA Champions League this season, none of us expected Paris Saint-Germain to come out to win it because they just lost their best player, Kylian Mbappe to Real Madrid and the manager, Luis Enrique was simply gathering his plans but look at him now, he's more confident to take the club to next level.
Favorite clubs are the teams that are under high probability to win the UEFA champions league and Barcelona fall in this category. Let's be straight, Barcelona was more focused and seen as a club that will reach the grand UCL final but ended up been eliminated in the UEFA Champions League. Barcelona did their best but got knocked out in the last minute by Inter Milan, the same team that got humiliated by Paris Saint-Germain 5 nil in the UCL final. Football is filled with mystery.
Say you didn't expect and stop generalising it, you are not everyone. And if you think because PSG lost few games in the group stages and struggled to qualify means they can't win simply means that you haven't been knockout competition because group stage performances doesn't really count. I have said it severely in the Champions League page that I personally started supporting PSG right from the group stages after that game be Manchester City which they came from 2 goals down to win 3 - 2. I saw through that team and tipped PSG for the trophy, so I wasn't surprised that they won because I already expected.