La Liga are threatening to sue them now,
“It is scandalous that a club like PSG, which last season reported losses of more than €220m after accumulating losses of more than €700m in prior seasons [while reporting sponsorship income at a doubtful valuation] with a cost of sports staff around €650m for this 2021-22 season, can face an agreement of these characteristics while those clubs that could accept the arrival of the player without seeing their wage bill compromised, are left without being able to sign him.”
I imagine it's at least partly down to bitterness over Madrid not getting him and Messi and Neymar leaving Barca, but they're right too.