I don’t know how this is so difficult for you to understand. Specifics don’t matter when we’re discussing a generalization. A successful game that makes its money back and then some more, that continues to be sold in relatively high amounts even after that, is more than likely going to be able to be supported for a while.
For some absurd reason you’re starting off from the perspective that there’s just no way that the game can make enough money. That it just inherently can’t survive on sales, regardless of the specific number.
If you honestly believe that a game that by all estimations sold several million copies and will likely go on to sell several million more is inherently just so unprofitable and underfunded it is completely unable to get its costs back and afford the (in comparison to actually making the game) relatively lower costs of making extra content then that suggests you have a very, very little faith in Fatsharks ability to make smart business decisions.
You, based on absolutely nothing, are making out that the game just wasn’t profitable right from the start. That they’ve decided it was a great business move to dedicate all those resources to making a game they know won’t do well enough. To develop a game that they right away knew wasn’t going to be able to support itself and that their estimations showed it wouldn’t sell, but they decided to go for it anyway. Yeah, what a great way for a developer to approaching making games, approving the ones that they think won’t work!
Stop disingenuously making out that “the current $18 that FS is getting for each sale” is the total sum of what they will have from game sales, because you know it’s outright not. That $18 is from a discounted price, so it’s temporary, and it involves you completely disregarding all previous copies sold as if they somehow don’t matter. We have an idea of how many copies it’s sold, we have an idea of how much a game like this costs to make, we therefore have an idea of if your claim of “There’s just now way it can afford it!” is likely to be the case or not.
And you’ve yet to address anything regarding how your claim of “Only $18 per sale! 2,666 copies per dev, it’s just TOO MANY!” was shown to be wrong, either.
Game publishers/developers tend to approve the making of games that they think are going to sell well enough, you know. Not the opposite as you’re claiming.