This ring magazine article gives great insight why HBO didn't pick up this fight.
The fact Klitschko-Chambers is not on U.S. TV is a new low

And I have to say I agree with the article.

Wlad just reminds me a lot of a Larry Holmes. A very good technical HW champion, but boring as fuk and reigning in a weak era. There's a reason why Holmes couldn't draw flies to his bouts and actually had to have a 50/50 purse split when he fought Gerry Cooney and was introduced 1st, which always is reserve for the challenger in boxing tradition.

Most boxing fans want the HW champ to be exciting like a Johnson, Dempsey, Marciano, Ali, Tyson, Holyfield, etc. They don't want robotic technically sound safety 1st HW champs.