But the same limitation applies to the contenders, doesn't it? As they're not _that_ much more powerful to make a real difference in this case, or am I wrong?
Err, no. The differences are pretty massive. The Samsung and Qualcomm processor cores are not only much, much faster but more sophisticated too. The Pi is very basic.
The Pi was also not the first of these boards, merely one that had great marketing and an appealing price point. My sheevaplug predates it by a couple of years (and is still faster)
The problem is not that RPi doesn't have the horsepower. It does - but you've got to use Videocore IV. Hopefully there'll be some good compiler with at least intrinsic support for it.