If Barcelona were able to hire Messi, then I assure you, they would definitely do it. There was simply no certainty this time and everything could have gone down at the very last moment, so Messi, already taught by bitter experience, did not wait out of harm's way this time until the very end without any guarantees for a positive outcome of the case and signed a contract with Inter Miami.
Speaking of Barcelona and Messi... I just saw that Inter Miami confirmed yesterday the signing of left-back Jordi Alba, Messi's former teammate at Barcelona.
Jordi Alba had announced his contract termination with Barcelona in May, after an incredible 11 seasons at the club, I thought he would retire there.
In the same way, midfielder Sergio Busquets, also left Catalonia to play for Messi's team in the United States... signings do not stop and it is expected (at least they are hoping) that Uruguayan striker Luis Suárez from Grêmio (Brazil) will also go to Inter Miami later this year.
I hope that Messi got it right at Inter Miami and that he has good seasons there before the next World Cup.