I do not concur that they are the two best. What big fights has either won since their respective losses?
I read that Thompson believes that Chambers knew he had a problem but didn't inform in time for the cancellation
Well, Chambers won an unnecessary rematch over a guy he comprehensively beat years earlier, but who'd gotten himself highly ranked (although he didn't look his best in doing so). Thompson cleaned out a handful of fringe contenders and for the most part looked decent against them. Resume aside - in h2h ability, they both have to be seen as right up there...no more than a couple of spaces removed from K2 (although K2 pretty much batters anyone behind them, including these two).
Chambers is a competitor. He wouldn't back out for no good reason. He knows what's at stake. Get off his (lower) back, man. He'll return and kick Thompson's ass.