This is still related to salary, because Barcelona is also experiencing a crisis due to the impact of this pandemic. So naturally, rumors of selling some players might be raised in the media, but with Griezmann willing to cut his salary even by 50% then that is certainly good news. Considering if Atletico are willing to pay Griezmann at the normal price, then of course Griezmann will move but because Griezmann's salary is very high and Atletico are not willing to pay that salary, Griezmann's return to Atletico does not happen instead Griezmann is willing to cut his salary to stay at Barcelona.
There is a third option that I think is not possible at all but at least it is a possibility. What if ATM paid Barcelona a decent amount, and then Griezmann took a salary cut to go to ATM? That way ATM could afford to get him and give him his salary as well, he wouldn't even have to cut his salary 50% in that case, a 25% cut would be enough I believe but if he does it 50% then it is all the better for Madrid to get him.
Barcelona just needs so much money so quickly before they start to suck big time, and they are playing Messi's final years and if they really want to keep him, being in this horrible economic situation is not the way for that, they really need a good roster right now before Messi retires or decides to leave, and in order to do that they can't just cut players salaries, they also need to sell some players to get more money and buy better players.