X11 Chrome Reportedly Outperforms Windows and Mac Versions
If you choose your abstraction carefully, you can hide expensive details from user space.
In the short term it may not gain you anything.
But if the abstraction lives and thrives, then much can go on behind the scenes to improve the situation.
Java is another example of this: they carefully designed the language so that it would be possible to make vast simplifiying assumptions and implement optimizations that really improve performance without impacting the "other side" of the wall. Originally java was slow, but hard work behind the scenes means that your java programs run much faster now, without any extra effort on the part of the application developer.
X Windows is a great example of this. Originally we had dumb frame buffers with no acceleration at all. And yet X provides an abstraction that allows lots and lots of hardware optimizations to take place.
The Windows and OSX abstractions for the display don't provide an API that allows these sorts of optimizations to be done behind the scenes. We have incredible display hardware with awesome features that go unused in these environments because the display abstractions do not allow for them.
