Firebreak was fine in my opinion. From the start Remedy was clear about it being the kind of game you pick up for an hour or so every now and then. Sort of like Left 4 Dead.

The problem was that majority of players wanted to have enough content in the game to play it multiple hours a day for months.

Personally, I think the game, despite it being a "failure", is going to be important in the future. It is an online multiplayer "live service" game built on Northlight. Remedy had to build networking and multiplayer capabilities into their in-house game engine. And it worked really well. This could allow them, in the future, to expand more if they want to.