Yes, they do. There is more than just the engine at play on compatibility. The main reason is actually usually the anti cheat.
Looking at Destiny. Game worked okay on Linux before they integrated Battleye, which HAS Linux support, but Bungie just doesn’t want to interact with it.
This is why it’s mainly larger developers that care about their community that implement Linux support. Take valve for example. Wonderful company that cares about their playerbase more than the average game development team. They have Linux support on almost all of their games as far as I am aware. Bungie is a decent company but most of their community doesn’t want to play on Linux anyway, so they won’t bother with it. However most teams that are smaller or care more about money than players won’t do it.
Valve is definitely an exception. I am not sure why, but it is pretty much in the open that Gabe Newell has a bone to pick with Microsoft and he has been throwing money at Linux for over a decade to break their monopoly on gaming. I’d argue that this has nothing to do with their love for the community and more so with Gabe’s personal vendetta against Microsoft.
Reality is that most game devs, most executives and most people in marketing don’t really care about Linux. It is good PR to support Mac and Linux, and some of the geekier developers will go the extra mile to support it, but I think it is common in the industry to assume that Linux users are not gamer, or that they have enough knowledge to install a dual boot. They don’t care in the sense that they don’t even think about it, its not even on the radar for most game companies. Most studios probably never even had a discussion about it. That is how irrelevant Linux has been to gaming. Hence why Proton is such a tour de force.
