Many good games do not use unity/unreal, as whilst they are packed with features, they are at their core flawed. Many people build their engines tailored to the

Many good games do not use unity/unreal, as whilst they are packed with features, they are at their core flawed. Many people build their engines tailored to their game, in order to get the best performance. In those cases it is 'effort' to port to Linux, as with any other platform. If steam machines don't flop then I expect Linux porting will become more mainstream and the process easier.