The Champions League can't just depend on one player. even though messi is a sensational player but depending on Messi in the Champions League and blaming him when he fails is a condition that is quite childish I think.
This requires team harmony and not just an individual thing when it comes to bigger competitions.
A team must work together which will produce perfect results. relying on one player is not very good let alone blaming him when he fails to advance to the next round. lionel messi has given all his best strength for psg this season and failure in the champions league certainly can't blame him.
psg must try to be even better next season in the champions league they need performance and coaches who have long experience in the champions league so that when they meet a strong team in the champions league they can cope with a strategy from a coach who is able to give tough resistance to his opponents.
It is not ideal to rely on one player to win the Champions league and even if you want to rely on a particular player it should not be Messi at his age. Neymar Jr even made better efforts than what is happening presently when he was signed as the hit man for PSG. Again I believe the ability of Mbappe to pull a solo effort in the Champions league than Messi.
Nature cannot be cheated. Messi ha played his prime and he is not much hungry to win any more thing because he has won all already.