However, until then, I am fairly sure that someone will reverse engineer the software and figure out how to emulate a server on their own.
It was done in the past (see bnetd). Blizzard didn't take kindly to it as it removed the need for a CD Key in order to play the game. They sued the developers under the DMCA and won.
However, for someone like Microsoft distributing something like a Windows 7 beta build, you're still going to want to spread the load across multiple servers on multiple continents and so on and so forth, which, yeah, is sort of what services like Akamai are all about. If Microsoft doesn't want to contract out like that, they could probably just do something similar with their own resources. I'm pretty sure they're big enough to be able to handle that.
Microsoft (at least through the MSDN download site) uses their own transfer protocol and file transfer management tool (Microsoft File Transfer Manager) to access the content. They do indeed use Akamai to host and distribute the content.
Refreshed by a brief blackout, I got to my feet and went next door. -- Martin Amis, _Money_