PSG is the richest club in Ligue 1 and that's why it has a standard that no other club can contest with them on winning the league for a long time now. Of course, if a rich investor buys the club like someone from Suadi, it is possible that after pumping funds into such club by buying world class players with great potentials, and a coach with high level of experience and success in his career, the newly bought club can transform into a very strong club that will be able to challenge PSG and win Ligue 1 from them.
The current football trend is more interested in other leagues, especially the Premier League, that's why big investors rarely invest in one of the clubs participating in this competition. I haven't studied much about Lique 1 regarding the mechanisms and regulations in this competition for its investors, but it can be concluded that the only rich club in this competition that has healthy finances is Paris Saint-Germain. If I'm not mistaken, PSG is also supported by Qatar, correct me if the information I get is not true. So, it would be very natural if PSG always dominates this competition. Moreover, the competing teams are constrained to compete with PSG based on player purchases. which in the end, there seems to be a spasm in this League and most people say the farmer's League. although true, I don't really agree with that label on any League that is always dominated by one team that always wins. Well, the question is apart from the points I said above, why don't many people look at the French League teams to become investments for big investors. if the logic is the same, in the end, teams that want to compete in this competition try to target talented players, whether it's an academy or young potential players to become classy players and be able to compete with PSG in the future. the problem is, it's not as easy as what I said. but what is certain is that PSG will not always dominate this league, there will be times when they slip and other teams break PSG's dominance so far, even though it might only be for one season.