why does interms not fight champions?

[sjewitt]

i was looking at the current boxing champions and thinking how people should really be unifing the belts more not only would it be good fights if a fighter had two of the major belts he would instantly have bigger selling power and become a bigger draw as it's quite rare so it seems to make sense, just from a couple of weights i was thinking how people like dzinziruk should figh bundrage or trout or even alverez if he defends a couple of times, as like i said if they did this and then there was a melti belt holder surelly the promoter and tv company could build them up better?

But my maine question is there are some interim champions like m'baye in welterweight and n'dam n'jikam in middleweight and i don't understand why they hav'nt fights with senchenko and golovkin respectivly? i thought once someone was an interim champion they had to fight the title holder mandortory?
these fights really should be being made don't you all think?

[GRANDSLAM]

Because if they do then the sancitioning bodies can't carry on taking 2 sanctioning fees. They'll only get one.