Without Mbappe, PSG would still be the dominant team in Ligue One, but currently what is of particular concern is that Mbappe's departure will affect people's interest in this league because most people are very interested in watching Mbappe, especially on international broadcasts, not in the stadium, and if that's true, PSG really want to buy Haaland, it is very possible not only to make PSG perform better but also to keep this league interesting for many people.
Erling Haaland is quite famous so his move could have a good impact on Ligue 1, but I doubt Manchester City will sell Haaland, statistically Haaland seems to be declining in the 2023-2024 season compared to the previous season but that doesn't mean he will continue to decline next season, in fact it could be so he will bounce back to get better.
I can believe that Messi and Neymar could attract attention in PSG matches, but Mbappe is not yet such a great player that PSG matches are watched only because of him. PSG set very high standards and spoiled their fans with the most expensive players, but as time has shown, this does not greatly affect the final result. And now Nasser al-Khelaifi says that they trust Enrique, they give him time and the opportunity to choose players. City will definitely not sell Haaland, so he need to look for other options.