PSG will continue to dominate the French ligue 1 if rich investors don't invests in at least five French Legue 1 clubs so that they can buy quality players they can use to build up formidable teams that can rival PSG and make the French ligue 1 title difficult for PSG to win. Clubs have expenses to cover, so I think the money each club earns at the end of a season isn't enough to buy them quality players and buy up a team that could win the French ligue 1 title.
They will of course since there's no other teams ready to dig it out with them so it has become there's until it other teams wake up from slumber, remember what attracts investors is the the potential of the club, every investor is looking at what they will get at the end, so which investor will want to do this and which is of the club will they invest in french league 1 that's where the problem is, if you look closely you will see that instead of any investor to invest in other clubs in the french ligue1 they rather do that in PSG because they already have a good team.
Since the money those other clubs get whenever their ligue finishes can get them the kind of players to do the technical know how, it means PSG remains the master of that ligue.