I think that it will never be too late for PSG as long as they stay as one of the richest teams in Europe. They will always have the opportunity in hand to build one of the most impressive squads to be competitive for the Champions League title. While this isn't a tough task for PSG the main problem is not about this.
The main problem has always been management issues. PSG have made so many changes in manager position of the team but none of them was enough to secure a Champions League title. Although Enrique has a different style of his own it is the truth that he is still a Champions League winner. If we see a good chemistry between then I don't see any hindrance for them to do better here compared to last season.
Manchester City also just won the Champions League title for the first time, so indeed it's never too late for PSG and that applies to all clubs. But PSG can be said to be more serious for UCL, they recruit superstar players and does not matter with the cost. Previously, Neymar was the player with the most expensive transfer fee. PSG were very serious about signing players but they were not very lucky and now their hope is in Enrique hands, seeing its historical achievements, PSG should be able to be better than the previous season.