If we are only going to look at statistics in an "additive" way (i.e. who has the most of a given parameter after a certain amount of time) then we are probably going to miss some things.
Messi scored 30 goals in La Liga last season, and was the top goal scorer. This is a fact. It is also a fact that the second and third goalscorers were Karim Benzema and Luis Suarez at 23 goals each. But Suarez and Benzema were both playing for teams with much lower attacking output. Both Real Madrid and Atletico scored 67 goals, Barcelona scored 85. That's an 18-goal difference. Messi himself can't account for all of that (he accounts for less than half the total goals). Both RM and Atletico had much better defensive records.
What does this mean? Suarez's goal tally was actually his second lowest since he's been in La Liga, and this time without having to compete for goals with Messi, or anyone. Would we have to conclude that he had his worst individual season? Or that Atletico, a defensive team under Simeone, is not a place for a striker to get the most goals?
Barcelona have topped attacking stats almost every season. They've now lost Messi, Griezmann, and Suarez. Aguero and Dembele have barely played this season; Braithwaite is injured, and Fati is a teenager coming out of a year-long injury. And they're at 16 goals. That's two less than Atletico, one less than Real Sociedad (at the top of the table), and three less than Sevilla. Statistical noise, basically. Somehow, after the bottom fell out of the team, they can still score goals.
Barcelona finished last season in third place, closer to 4th than to the top of the table. It was their worst finish in ages. There's a good chance that this season they end up in the same position. What then? Does that mean that Messi did something amazing last season by dragging them to 3rd, but that can be replicated by Memphis and a teenager coming out of an injury?