I think your mention of OS drawn widgets brings up an interesting point of discussion. In desktop environments for the most part windows apps look like windows

I think your mention of OS drawn widgets brings up an interesting point of discussion. In desktop environments for the most part windows apps look like windows apps and osx apps look like osx apps. A consistant look and feel across applications on a platform gives users a familiar and comfortable experience. This has been a detriment of java desktop apps for years as they appear 'foreign' to the end user. Is there perhaps an argument that the web as a platform is missing out on this benefit of consistency?