That's an excellent way of phrasing this situation, actually. Android isn't the only competitor Apple's got. It's not iPhone versus Android. It's that versus Windows Mobile versus Blackberry versus...
I also don't see what open source would have to do with improving sales of the device. If Android succeeds, it'll have to be because it does something very special that RIM and Microsoft - and especially Apple - haven't done yet.
Considering the reports say that within another quarter Apple might have more iPhones out than there are versions of Windows Mobile everywhere, I'd want something a lot bigger than "This is a good product" to suggest Google has a chance of toppling Apple.