The reason for PSG to usually fails in the Champions League is mostly because of their unbalanced team and the players they bought just because the players are famous, I think they need to have a better management team and we know other reasons for them to only win French League is because if not having a good competitor in France to make them ready for the harder matches in the champions league.
I agreed with you partially because just spending money and having trophies not working they need to be understood ground realities as well which are also important like we have in Manchester City and few other clubs they are using their funds wisely and having better results but here at PSG they are doing all things just with the big names which are surely not guaranteed for the success they also need to work on strategy and better depth between players which bring better rhythm which is also important for the success right now they have good coach now just need to understand few things and allow him for the important changes and also allow him for long term strategy because with this most chances they can fill their dream of having Champions Trophy into their pocket but if they fail with this coach then surely things could be more than worst for them in coming years.