Finally Sony has opted to make a good business decision here. Firewalk wasn't working on anything else besides Concord. But to put it in perspective, I did some napkin math on the subject.
ET The Extra Terrestrial was previously regarded as the biggest flop in video game history. This is because the licensing for the IP was supposedly around 20-25 million dollars at the time. Atari 2600 games usually cost somewhere between $3 and $5. It sold 1.8 million copies but that's no where near enough to cover the licensing fees much less the cost of development and manufacturing, distribution etc. of the cartridges.
Concord supposedly cost upwards of 500 million dollars. We know this because Probably Monsters, the previous owner of Firewalk had already sunk 200 million into the game and after nearly five years of development had little to show for it. It's unlikely that Probably Monsters didn't at least get what they had in Firewalk and in Concord back out of it when they sold it to Sony. Though the actual purchase of Firewalk was for an undisclosed sum. Sony found the game in such an poor state that it was forced to assign additional studios to help Firewalk finish the game. It took three years and another 200 plus million dollars to complete.
Concord reportedly sold 25,000 units. PSN numbers for Concord show something like a little over 1,000 concurrent players. For Steam, we know it never broke 697 concurrent players. I'd bet money the "units sold" were physical copies to retailers. Meaning Sony is counting sales to distributors for retail stores and those were not actually copies that made it into the hands of players. If they had actually sold 25,000 units, you'd expect to see at least a few thousand players online concurrently on launch weekend at the very least as people gave the game a chance.
That didn't happen. It's more like they probably sold something like 800 to 1,000 copies on Steam and maybe 1,500 to 2,000 copies on PSN. With those numbers they couldn't justify even keeping the servers online for it. Most likely the servers were probably IaaS type servers from AWS or something and that could cost 10's of thousands of dollars a month per server. At $40 for the game and having no monetization built into the game, there was no way they'd do anything other than bleed cash while they reworked the game.
Given the complaints about the game, they would have needed to improve the graphics, create new multiplayer maps, redesign all the characters, rework the combat to something better than "mediocre" and all those fancy cutscenes, dialogue etc. would need to be redone. In short, the game needs total redevelopment and that would likely cost them another 200 million dollars over the next 18-36 months or more.
Firewalk flat out didn't have the development chops to do any of that or the game wouldn't have been in such an unfinished state when Sony got ahold of the studio. It was never coming back as a free to play game. You can't monetize a game by selling cosmetic items for characters so ugly that it breaks Rule 34.
Rule 34: If it exists, there is porn of it.
Rule 34a: Except Concord. No one wants porn of that.