And if that were the end of the story, I think we'd be able to call it a day. But everyone has this funny expectation that that old code should keep getting faster with newer GPUs, in spite of the fact that GPUs don't work the way those programs were designed to use them.
Getting modern GPU performance, or anything close to it, through the crufty old immediate-mode API code is like drawing blood from a stone. Eventually developers need to take some responsibility for the code they're maintaining and migrate to a more modern API. Even on the desktop they'll have to do this - when their customers ask for modern GPU features, they'll have to move to OpenGL 3, which doesn't have immediate-mode either.
Getting modern GPU performance, or anything close to it, through the crufty old immediate-mode API code is like drawing blood from a stone. Eventually developers need to take some responsibility for the code they're maintaining and migrate to a more modern API. Even on the desktop they'll have to do this - when their customers ask for modern GPU features, they'll have to move to OpenGL 3, which doesn't have immediate-mode either.