Maybe more brothers would consider it if the money was right...
Klitschko vs. Klitschko would be an insane money-maker, with the right publicity. Huge numbers of boxing fans, even some of the most half-hearted ones, would spring for the PPV.
On top of that, every guy, boxing fan or not, who ever imagined what it would be like to duke it out for real with his brother (i.e., every man alive with a brother) would at least consider tuning in.
Can anyone here honestly say he wouldn't spring for the PPV?