The reactions in here are, as always, completely over the top in both directions.
There's no denying Messi had a very slow start at PSG. Yes, he also had good games without scorers and people overlook that but it's also clear that Pocchetino faces a real problem when Messi, Neymar and Mbappe on the pitch. Tuchel's work at Chelsea should speak volumes about the importance of a cohesive and hard working unit in modern football. And that's hard to accomplish when you one of your attacker runs only 8.3 kms and another one (Mbappe) only 7.9. And Messi is part of this problem, like it or not.
On the flipside, saying Messi "is finished" is also a very superficial take after the season he just had and the Copa he played. You also see in his plays that he's still among the best out there: Finishing, dribbling, passing, it's all there. And he always ran as few as he did against City. It is just becoming more obviousand gets pointed out more frequently when things don't work out, especially if the team looks a bit disjointed and he doesn't get on the ball in dangerous areas enough.
The really interesting question isn't if he's finished, the question is if players like him, Mbappe, Cristiano and to a lesser extent Neymar are still worth their "laziness" against the ball in a modern game that's been dominated by teams that consist of 11 hard working players those last few years.
And if you come to the conclusion that no team who wants to win the UCL can allow itself the luxury of carrying such a lazy player, one has to ask the question if any player without exceptional work rate can really be labelled the best in the world anymore, regardless of the skills he possesses.
Right now, it is definitely remarkable that the teams of the superstar players (Messi, Ronaldo, Mbappe, Neymar) have been underperforming for at least 3 or 4 years. There are two explanations for that:
a) They didn't in truly elite teams, especially regarding the coaching, but would still excel in squads like City or Bayern like Messi did for Pep and Cristiano for Zidane while being just as lazy as nowadays
b) Football has evolved and the days of the divas have finally passed. Tuchel's performance at Chelsea seems to imply this. Anyway, this would also mean that teams like Pep's Barca wouldn't compete these days either, because this one also carried Messi's low work rate.