Depends. Intel has two variants of the next Atom to come out. One is full blown for netbooks and gets the same if not better battery life while performing better. The second is for mobile phones and the such and is said to be able to give two weeks worth of music playback. Its designed to shut of the parts of the CPU that it doesn't need depending on the task.
So I would say yes, Samsung could. But Samsung also plans their own CPU in the future (called Orion). But they also work closley with ARM so they tend to use them.
But I would say that Atom could give 1+ hour on the Galazy Tab. Its a good processor and not as power hungry as people think.