The commercial goal of the advertising is not to drive IE usage vs Chrome/Firefox on Windows - it's to get people to buy windows machines. They're [re]building the IE brand, dispelling negative perceptions around IE (and Windows, by association) and presenting IE as a superior browser to drive OS/computer purchasing decisions.
None of those goals are served by a cross-platform version - in fact, it would only present a risk if the quality and experience was not similar or better to the native version.
Didn't the last little video propaganda just note that IE "sucks less" than it used to, and that all people who dislike IE are trolls? Wow, that's really effective. IE propaganda like that surely makes me want to give up my browsing experience and switch to Windows.
Don't forget that you are not likely to be the target audience. I'm not a marketing person, but my guess is they're looking to staunch the flow of home users away from windows, and assuring CTO's that the browser won't continue to hold the ecosystem back.
Attracting back Apple users or trying to convince Ubuntu fans to switch to the dark side probably doesn't feature in the plan, for now.
Filed under link bait, IMHO. There are so many better opportunities, even Windows Media Player for Mac would make more sense, if it was everything that people want iTunes to be, and you could use it as a Trojan Horse for Windows Phone sync, online services etc...
1.) Maybe because it would be pretty hard to port IE to an OS with a pretty different architecture and I'm not even sure what would be the potential gains of doing so.
2.) Safari is based on WebKit so a lot of the cross-platform compatibility bitchwork is already done by the WebKit project, not really Apple.
3.) It appears that Safari for Windows is dying if not already dead.
I'm pretty sure that nobody but web devs actually used Safari/Win, so I understand why Apple want to spend the engineering time porting something that users didn't care about. But how is Apple not shipping Safari on Windows (or Android for that matter) different than Microsoft not supporting IE on Macs or Linux?
The difficulty of porting the application is not the issue at all. There was a Mac OS X version of Internet Explorer, and it was even the default browser in OS X. Microsoft deprecated it in 2003 shortly after Apple released Safari. http://en.wikipedia.org/wiki/Internet_Explorer_for_Mac
The potential gains, of course, would be browser market share.