Whether or not Android can pull that off is irrelevant. It has changed the smartphone landscape probably more than any open source project has changed any other market. HTC and Motorola have jumped in with Android devices in a big way, as have other handset makers.
That isn't the only open source project though in the mobile device area. Funambol has profiled ten companies, without naming names, that have adopted open source for at least some of their mobile infrastructure. Obviously some are doing so just by selling an Android based device, but others are using cloud sync solutions. Funambol, in fact, is one of the providers of a server side sync solution for mobile devices. You can read the paper to get a feel for what these companies are doing, and why open source is as successful as it is for this area.
It makes you wonder why open source hasn't taken off as well in other areas, namely the desktop. Linux is a serious contender with real market share on servers and embedded devices like firewalls and routers, but when it comes to the desktop, you'd be hard pressed to find someone running Linux on their PC in your neighborhood. You may find a few that have it installed in a virtual machine or in a multiboot situation, but probably not too many that use it exclusively, or even primarily. Even open source software such as Open Office hasn't made too many inroads where it counts.
Part of the reason for this may just be expectations. People expect to be able to run certain pieces of software. iTunes, Quicken, Office and Photoshop are just a few examples. You can generally load these onto a Mac or Windows PC with no problem. There are open source alternatives to many of these that run fine on Linux, but they aren't the same thing - they aren't what people expect. People don't run Windows, they run applications and they want an OS that will support their apps.
The mobile phone market is different. People are used to getting a new phone every year or so and have come to expect it won't work much like their previous phone. It just needs to do what they are used to doing - making calls, storing contacts, email, web browsing, etc. The cooler it looks, the better. Until the iPhone launched, third party apps being installed on phones was a relatively minor phenomenon. Windows Mobile and PalmOS supported it, but you'd be surprised how many people never installed the first thing on those phones. It was either too much of a pain (you had to get desktop connectivity software to dock the device and install apps from the PC side) or people simply didn't know about it. the iPhone App Store changed all of that in 2008 and now everyone expects to be able to install apps on their phone.
There are, however, no must have killer apps for mobile devices. Generally, you can find an app to do what you want on any of the major platforms. This is why I think Android is going to thrive. It is a competent platform capable of anything the competition is - just like Linux. The difference is, Android's customers aren't dying to get a specific app for their phone. They just want something that performs a specific function. The expectations are different. On a PC, you need to use Excel to create a spreadsheet that you can reasonably expect will be usable by anyone you email it to. On a phone, you would never create a complex spreadsheet. As long as you can view what has been emailed to you, and perhaps make minor edits, you don't care if it is Excel Mobile or any of half a dozen third party alternatives available on the various platforms.
Until there is a killer app that will keep people anchored to a single platform, a well funded open source platform will thrive. I don't think there will ever be a killer app like that for phones. I think the only thing that will keep the number of mobile operating systems in check is the carrier's willingness to support them. The key players today are Symbian, Windows Mobile, Blackberry, iPhone, WebOS and Android. Each is just as viable as the other. I personally think six is too many, but I'd wager that even if it got down to three, Android would be one of them because of the advantages open source offers when it comes to flexibility and customizations, both of which are far more important on a phone than a PC.
I never really touched on the back end where open source also has a respectable showing. You can read more about that in Funambol's report. The point is, open source has, for now, a unique position in the mobile space. In just about every conceivable area, open source is a major player, keeping big boys like Microsoft and Apple in check.