A recent post on a MMAjunkie reveals that more than 9 out of 10 MMA fighters with "Ring Rust" loose fights.
It's also likely that UFC/Zuffa, being a Billion dollar business, has been armed with detailed stats of how "Ring Rust" can forecast the winner and looser of a fight. By controlling the outcome of a fight the promotion can limit the number of fighters it will build up as "top of the food chain", limit the number of fighters it will offer top pay, and allow it to shape future PPV fights that will deliver more profits.
For example, just a few of the fights in the last 2 years with Championship implications include these "ring rust" opponents with at least a 9 month layoff:
Randy Couture 14 Months - Loss (KO - Lesnar)
Rodrigo Nogueira 11 Months - Loss (TKO - Mir)
Roger Huerta 9 Months - Loss (Dec - Florian)
Kenny Florian 9 Months - Loss (Sub - Penn)
Sean Sherk 10 Months - Loss (TKO - Penn)
Thiago Alves 9 Months - Loss (Dec - St-Pierre)
Akihiro Gono 11 months - Loss (Dec - Hardy)
By selecting "ring rust" opponents the UFC can more easily predetermine who might win a fight and control future PPV profits.
For example: The UFC has already stated the winner of the Carwin/Mir fight will fight Brock Lesnar when he returns in the summer. On the surface it appears as though the UFC has no control, but the history of ring rust suggests the opposite.
This weekend's fight between Frank Mir and Shane Carwin has Carwin coming into the fight with over 1 year out of the ring. Ring rust for Carwin will give Frank Mir the edge to win and Mir would be the next opponent for Brock Lesnar.
A Lesnar/Mir 3 fight would be a much more profitable PPV, and potential future fight between the two, than a Lesnar/Carwin fight.
Once that Lesnar/Mir 3 fight takes place, Brock Lesnar's ring rust of more than one year would serve Frank Mir up as the Champ. The UFC can then tout Mir as "The best" since he beat Lesnar a second time and that would most likely deliver a Lesnar/Mir 4 and Lesnar/Mir 5 soon after.