Linux graphics you mean? The compute ones are fine.
It's not as much of an issue about supporting old versions, it's just that new versions of Linux breaks the drivers since they don't know what's in it.
But such servers have no need to, for example, suspend and resume correctly. Or handle hot-plugging of displays correctly. Or install updates in a completely reliable manner. Or include the 32 bit support needed for Steam to work.
It's not as much of an issue about supporting old versions, it's just that new versions of Linux breaks the drivers since they don't know what's in it.