They transferred important players and paid high transfer fees. The only reward for the money they pay is the expectation of success. If PSG can achieve success, Enrique can stay at the head of the team for a long time. In my opinion, Enrique should be able to make it to at least the quarter-finals of the Champions League.
Unlike you, I'm not sure at all about Enrique being successful in PSG. In fact, PSG had many superstar players in the last season they could help the team like Messi but they didn't have a good coach like Enrique in his team, Now when some players left PSG for the other teams, Enrique started working there but still I don't think if Enrique is enough to help PSG improve the team.
I think PSG still can't earn achievements in the Champions League.
Much money were spent during years in fact without much success except for Ligue 1, partially because there isn't a real threat for them. Most teams drop points easily and more than what PSG is doing all the time.
I agree with you about Champions League, I doubt they could go to finals or even reach semifinals. In Ligue 1 they could claim back the first spot in the next rounds if they stop losing points and especially that Monaco will face Lille and might drop points.