~Snip
Ligue 1 will not lose its popularity but PSG will lose its dominance. I actually think that without Mbappe, other teams will have the opportunity to eliminate PSG's dominance. Yes, PSG is still the #1 favorite for now, but at least they won't be as dominant as they were when they were with Mbappe. We might be able to see where PSG has to fight to win the league championship, unlike this season where PSG really dominated Ligue 1 with a goal difference of +48 goals and collected 76 points, 9 points ahead of Monaco in second place.
What makes you think that PSG will no longer dominate Ligue 1 now that Kylian Mbappe is gone?
I don't think Mbappe is the only player who can score goals when he is the target man. Other players such as Goncalo Ramos and Randal Kolo Muani can also be expected to be good if Luis Enrique makes them target men. So I don't think PSG will lose much to be proud of next season, that includes their goal productivity.
As a result of Mbappe leaving, the two existing center forwards are likely to get main places in Luis Enrique's squad. Ramos or Muani will shine even more next season, so I don't think PSG will lose ground in dominating Ligue 1.