From the 3 seasons that I tried to show in the picture, Barcelona managed to score more than 80 goals every season even though they didn't win the title. At that time they still had Lionel Messi and Suarez. But this season they have only managed to score 32 goals in 21 match, it is a result that is not imagined by everyone about Barcelona.
Previously, Barcelona has some great strikers who are always consistent to score almost every match. Not only Messi and Suarez, but they also have Griezmann and Dembele who still played quite well at that time. These strikers were supported by good midfielders such as Rakitic and Vidal. Now, those players have moved to other teams and Barcelona cannot find the best players to replace their roles. Considering this matter, I am not surprised to see a lack of goals made by Barcelona nowadays. I even predict that they are difficult to score more than 60 goals at the end of this season.