If Messi is going to decline PSG's offer of a new contract, i don't think it is ever going to be bacause of the money they are offering, PSG has enough money and they are paying Messi very well, i think Messi might leave because he feels unwelcomed, especially by the fans who have booed him a couple of times, both this season and last, thus Messi might go to a club that adores him, and there's no better one than Barcelona.

Having said that, i don't quite understand the situation in Barcelona, they let Messi go because they are broke and then they start buying many players with a high salary range/scale, and now they want to bring Messi back, how do they now intend to pay him.