The possibility for Messi to stay is PSG is very low and I'm sure Messi is trying to choose his next destination for next season because there is not a good situation for him in French and he can't play on a team where he can't be respected, even PSG is trying to find a player to replace with Messi and they don't have much hope about this player for next season.
I think the period of popularity as a great player Messi is almost like CR where you have to choose the last club before retiring from football later, PSG doesn't need to hold Messi for that, I just see Messi's declining performance so I'm not sure he will stay at PSG for long, messi can't bring the PSG team to the CL final and I think PSG also needs new talented players who can bring PSG next season as well as being able to reach the CL final.
I think PSG needs to make a player overhaul as well as add their midfield to make this club good again next season, even though I know PSG can win the French league this season but the failure in CL yesterday must have disappointed all the supporters, the only best way to I see PSG doing better next season, namely reshuffling their squad team.