Never before have I seen PSG as high among the bookmakers as now. Of course that has to do with Messi going to the club. They are top favourites, otherwise it would be a matter of time before they would become champions. Even without Messi.
They have spent the most money this transfers season and Messi is nearly confirmed. They will win the league and they will probably win the Champions League. PSG will be punished for overspending in a couple of years but they would only achieved their goal of champions league. They will be unstoppable for the next couple of years.
Having superstars and spending a lot of money is not the main indicator in football! A good example is last year's league, where Barcelona, Bayern, PSG and Real Madrid lost in 1/4 and 1/2...
PSG can undoubtedly win the home championship, but they might not have enough experience for the Champions League... Although I also think they are worthy of a final this year!
We have to keep in mind that if there are a lot of star players in the team, there is more conflict between the players. If there is more conflict between the players of the team then it will be very difficult to win against a strong team. Messi may not have ego problems. He will be able to adapt well with Neymar. But Mbappe and Ramos have lots of ego problems. So even if PSG have plenty of star players in their squad, it’s hard to say how effective its results will be.