An OEM can already choose, they want Firefox, they ship Firefox. Ok, most don't because its easier not to fiddle and end up just shoving on the usual crap bundled software.
This is nothing more then and EU trying to do what they did with WMP. They forced MS to ship a version without it, and what happened? everyone ignored it since users wanted it integrated (shipping a handful licenses across the EU in 18 months is not a sign the EU did what consumers wanted), they wanted a media player integrated.
We have Windows shipping with IE, we have the whatever Apple products shipping with Safari, we have every Linux distro shipping with some browser justable (and yes, some ship without but the majority come with one). Is this about allowing us to choose at first boot a Mac running Firefox or IE? no it is not. Is it about allowing me to choose Opera on an iPhone on first boot? no it is not. Is it about allowing me to run a browser other than the distro comes with on first boot on Linux? no its not.
Like them, or loathe them, Microsoft provide everything Joe Public wants out of the box (and a lot more for when they want more later), but they fit the market. The EU running around after a couple of companies is just crazy when it will result in nothing but a harder time for the public. Yes people will whine its in there best interest, yet the majority of users like not having to think. They like everything just to be infront of them.
Flocke, shipping a demo version of an enter OS again does nothing but aggrevate the customer. Windows is a component, the OEM and in the end the consumer already chooses to pay for it. We have a choice of machines shipping with Linux, which are cheaper. But do they sell as much? no. Because no body wants them! Dell allows you to choose your OS on some machines. HP does the same. Many others also. If you really want no OS at all, just buy the components yourself and build your machine your way, or get an independant retailer to do so for you. There is realistically only one walled in garden and thats the Mac, but as always everyone just ignores them as they never do anything evil or find new and innovative ways to extract huge amounts of cash from its userbase.
Sony at one point shipped Vaio's with Firefox preinstalled. They then changed back to IE. To be honest have no idea why, but the choice is there for an OEM to ship an alternative browser out of the box. The majority don't and frankly can't be arsed to do so.
Shipping a browser integrated is a huge aid to the consumer. Without one you bring in a confusing choice for many. And that scares many users who want as few questions as possible. They don't want some browser, to them they have no clue what a browser is and will end up saying no to installing one, then wonder 10mins later why the internet no worky, and insist they never clicked anything. If the consumer wants an alternative browser, nothing is stopping them from getting online once the machines installed and installing whatever they like. They have the choice already!