Reason of being no OSX Intel in retail is because all hardware that support OSX Intel already shipped with it. There's no older hardware that need to upgrade to it. Unlike PPC, which there's still many machine that might shipped with OS9 or 10.1 - 10.3 need the upgrade.

If you have the "downloaded", "copy from friend", "burn by my friend" or even "Lowyat plaza" version, shame on you.

If you own more than 1 same model of Mac and want to save some $, maybe you can eBay the installer DVD later. There might be some buyer that lost or damage their DVD. Don't ever hope Apple retailer will bother to remove the OS and give you discount.