Playing devils advocate a little bit here but ultimately didn't the UFC cancel this show? I know this entire forum is putting the cancellation of the show on JBJ and blaming him for all the fighters that will now go without a pay day... but isn't this also on Zuffa?
If the UFC really wanted to they could've proceeded with the show, lowered PPV price and have Chael fight Vitor Belfort in the Main Event.
Like I said, kinda playing devils advocate. I think JBJ was a huge puss in this and GJ once again showed his true colors, but at the same time Zuffa made the call to cancel the entire show.
This is the point everyone here seems to be missing. My hunch is that the reason they didn't go ahead with a Sonnen vs Belfort main event is that they would have had to offer the ticket buyers a refund option. This is compulsory in Nevada when the main event is changed, unlike, say, Calgary where they just recently pocketed over $4 million in gate revenue and split town under similar circumstances.
Things don't work that way in Nevada and Zuffa must have sensed the demand for ticket refunds was going to render the event unprofitable and decided to pull the plug and put the heat on Bones and Jackson. They have managed the message masterfully so far and everyone is frothing at the mouth, raging against Jones/Jackson when the idea of a Sonnen fight was totally ridiculous to begin with and people really should be pissed at Zuffa for watering down their product to one fight per event strength and thus leaving every card held in a strong regulatory state one injury away from cancellation.
They went ahead with UFC 137 after GSP blew his knee out because they had a decent co-main even and several other interesting fights on the card. 151 was shit outside of Jones/Henderson. That's on Zuffa.
Given the short timeframe, and options available. I still think Jones is to bear the burden. Listening to the conference call, Zuffa clearly made the impact obvious to Jones before going public. ie Dana spoke about Hendo wouldn't have been allowed to fight regardless after they flew him to Nevada, machida was in the air to Brazil, sonnen was on his way back from hospital with his gf, from visiting her dad etc. Too many stories for zuffa to have clearly not tried to get Jones to fight.
Just my opinion.
Champs are the best for a reason??
No one can tell me they have never done overtime at work or helped train someone new.... this is Jones version of that. Its his job, he didn't step up , simple! 
He's not a fighter. He is an athlete who is good at fighting. I also believe the comain was scrapped because of an injury weeks ago, but I could be wrong.
Man lol! Dana at the conference call "we can't make Jones take a fight, but its probably not a good idea to do it, cause he starts doing these things, we'll have another conference call about him"
Lol! Jones was sssoooooo to blame!
But to the op's point, a Sonnen vs Belfort main event would likely have triggered a torrent of refund requests from enraged ticket holders, and in Nevada, unlike the recent example of UFC 149 in Calgary, the fight promoter is required by law to offer a refund option to ticket holders. They must have anticipated a huge demand for ticket refunds and also a huge impending bath in lost ppv revenue and decided they couldn't make money on a quickly thrown together Belfort vs Sonnen headliner.
As the recent Calgary UFC 149 debacle illustrates, they didn't cancel the card out of any sense of loyalty to ticket buyers, that is for certain.