I don't think that PSG dominance in the French ligue 1 is only due to the fact that PSG is rich I will not agree with you on that because in today football there is financial fair play rule that applies,so a team can't go and bring money from another source of income to sponsor a team the truth is that other teams in this league are not just serious about competing and this is not only limited to the French ligue they don't even do well in European competitions.
PSG's wealth is not really from another source, the win the Ligue 1 almost every season and they win other sub league titles plus their jersey sales which most other teams do not get as much so their wealth is not far fetched and they also utilise it well with the quality of players they bring in so it may not be all abi their wealth, but it does plays a very vital role that will continue give them that topping edge which most other teams does fail to get so you cannot dissociate their success and strength from their wealth, they all work together.
Paris Saint-Germain is also very successful in terms of player transfers. They have quality young players and are selling many of their academy players to Europe. Now that their team is in near-perfect form, they're not rushing to make transfers. It's also worth noting that they've won the French League championship every year. They generate a significant portion of their broadcasting revenue and are successful in the Champions League. Therefore, I also believe that Paris Saint-Germain's revenues aren't particularly high, nor are they anything to sneeze at.