I don't know what the current situation is for Barcelona regarding their financial issues, but as we can see they often find ways to make it possible somehow. Last time they didn't, that's true, but if they have a long time to handle a specific problem they might be able to solve it.
As far as the sportive side goes it could still be interesting to see Messi go back and play behind Lewandowski, Dembele and Torres or Pedri etc. They would find a position for him where he could still offer a lot of value to the team. Lewandowski would certainly be happy about it because he knows that there is no player providing better and more precise assists than Messi. That is what Lewandowski loves.
For Ligue 1 it would be bad news. Think about the worst case when Real Madrid would get Mbappe and Messi leaves as well, Ligue 1 would get hit hard in terms of public interest. Neymar isn't really a reason anymore for people to watch PSG.
Having a huge debt has been making barcelona has so many limitations to buying the new players. Barcelona hasn't even paid off the debt yet. Barcelona didn't have financial support to bring back messi to the camp nou. There must be many players to be sold by barcelona first if the club wanna sign messi back again to the club.
The future of messi is not yet clear. Messi was also making the situation even worst in PSG. It seems like he will be having more chances to leave from the club rather than stay even longer. Neymar will be leaving PSG,.
I guess that there will be so many people moving their eyes from PSG to another club that will become a new club for messi.
in my opinion messi shouldn't leave PSG, they are a great team he can retire from and will be remembered forever, another or even better saying the only good team for messi would be manchester city, but from what i see i wouldn't be surprised to see messi going on a shit team, like some arabia team, i hope common sense remains in messi's head
about neymar, it is known that neymar's behavior off the field is not good behavior, he doesn't play much every season, he spends more time off the field due to injury, with the high salary he earns I don't see any reason why PSG keep neymar, PSG can sign another player cheaper and better and PSG needs to reduce expenses, in my opinion, we can see the case of real madrid, they are not making high expenses in the last seasons but they have good results