Only Real Madrid has won the Champions League back-to-back. PSG can also try to create another record for themselves next season by defending the title, but I don't that's possible because they would still be carried away with the excitement of being the defending champion and might lose focus on taking their matches seriously like they did this season.
The rest of the teams will not make the same mistake every time. At the beginning, PSG was not a very strong team, at one point it seemed that they might be eliminated from the group stage. But they managed to extend the elimination period much longer and finished the Champions League with the title. Our expectations were around Real Madrid, Arsenal, Liverpool or Barcelona. But those expectations were not met at all and Inter Milan and PSG entered the final from outside the expectations. Here, of course, the fate of the two teams worked, because the mentioned teams were stronger than them. But maybe this will not happen again and the mentioned teams will not make the same mistake next time.
I agree that there was one moment when I thought there is no possible way for them to win the CL and in the past PSG wasn't able to get their game finally going and beat the big teams. This time they saved themselves into the playoffs for the knockout rounds and from there on, PSG quickly became one of the favorites.
However, I was still expecting that they will fall back into their old shape and the same problems are going to reoccur . But not this time and this is why I think Enrique and PSG fit together very well. They seem to respect him and he is able to keep them own to earth even when they lead their domestic league by 20 points.