They make money on hardware, they can't make money on search but google can.
Have you ever read any corporate histories of Sears, Walmart, et al?
As soon as you are the dominant market for any manufacturer's product, you take over their profits.
Now this is usually done be either by demanding lower prices until the manufacturer had almost no profits left, or in the case of family companies that felt loyalty to the workers, until the family could no longer afford to run the company (there are some dramatic anecdotes of frantic owner's giving up and trying to hand the keys to the sellers. Of course the sellers refused - the manufacturers would be the only ones capable of wringing out those last few dollars).
In Samsung's case, it only makes sense to demand that Google start handing over either a percentage of their mobile sales or simply paying Samsung a set amount per handset. (Of course, it might make sense to start smaller. For example, giving Samsung first access to new releases for 6 months to eventually demanding exclusive access to Android on platforms for which they have products.)
If you've got enough profits to be worth worrying about, you never, *ever* want to have just one viable customer.
Honestly, I don't think Samsung is quite at that point, but it's getting pretty close. Outside of the slashdot-crowd (which, let's face it, is noise in the sales figures), almost everybody I know thinks of themselves as buying a "Samsung", not an "Android phone".