Wow. Just...wow. Sure, Gmail could enable Exchange support. But it is entirely possible that they would prefer not to do so (it is rather a resource hog) and use some other solution. I'm sure that Apple would be glad to work with them to help them enable it. Moreover, since most people probably use the default setup tool for Gmail accounts, even if Exchange support were enabled on Google that would not automatically enable push for most users. Apple would still have to update the setup tool to use the exchange server instead of imap or pop3.
Why you are so angry at the idea that Gmail might have to work with Apple to get push enabled is beyond me. But I imagine that, however they chose to do it, it would, as jav6454 said, involve some phone calls from Google to Apple.