The Pac-12 just doesn't have the rabid fan base that the SEC and B1G have. Even the ACC and B12 fan bases are larger/more loyal than what the Pac has to offer. The Pac has the advantage of big media markets (LA, SF, SEA, Portland, PHX, SLC, Denver, San Diego, etc.), but those are all pro sports type towns. Very little attention is paid to the college teams unless they're winning.
For the long term, if the Pac is going to stay (get to) on par with the other P5 conferences, they're going to have to make some radical changes. Some have been mentioned above...move the home office to somewhere like Sacramento where it's not so expensive...pay their commissioner a reasonable salary...etc. But they'll have to go deeper than that. In football, they MUST get themselves some exposure outside of their footprint. They need to make a concerted effort to play games at SEC, ACC and B1G schools. Whatever it takes...even if they don't make as much money as they should. USC, UCLA, Washington and Stanford have got to get games scheduled in the Central and Eastern time zones. And on top of that, they've got to get the marquee schools from the ACC, SEC and B1G to come to the west coast. Again, even if they have to take a little financial hit, they've got to get schools like Alabama, Clemson, Ohio State, Michigan and Florida to play west of the Rockies. Cal and North Carolina did a home-and-home recently, but in the college football world, that match up is not going to move the needle. Sending Indiana to play Arizona or Virginia to play Utah or Kentucky to play Oregon State is not going to cut it. The Pac needs to be in the deal-making business...they need to get the crazy college football fans from the marquee schools out to the west coast to create some serious ticket sale demand and high profile TV exposure.
But those who hope in the LORD will renew their strength. They will soar on wings like eagles; they will run and not grow weary, they will walk and not be faint. Isaiah 40:31 (NIV)