Yes, there are a lot of stars players there, and they have been there for years. But how much did they help to win the league?? there were unable to help PSG win the champions league.
Yes, and maybe that's a very logical reason for the PSG club in terms of recruiting Messi, but I'm also not sure that Messi can bring PSG to become champions because the problem of winning is always inseparable from luck, even though there are many star players there.
Maybe that's why they recruited Messi. As we saw that with even a bad squad like Barcelona's Messi was able to do wonders. Barcelona can now feel that how important Messi was for them. He single-handedly carried them to success. Maybe that's why the PSG board thought that Messi will be able to help them get the CL trophy. So far this season PSG do look like a contender for the title, let's see what the future holds for them.
If for title challengers this year PSG do have the potential for that and even in the past before Messi it was also seen like that and in Barcelona before messi ended his contract with them they also lost a lot, so try to look at each club from two points of view so that can balance between winning and losing.