Think of how many pre-arb players there are. If you doubled their salaries, it would be a drop in the bucket for owners but would probably get a big chunk of the players to vote yes on any contract. Shorten the arb year by one, and they'd probably have a deal, even if they screwed the players everywhere else.
Management did this at a company I worked for. The lower tiered workers outnumbered the higher tier, so the contract offered dramatically shortened the time it took to get to top tier, thereby giving massive raises to the lower paid workers, while they added nothing to the top tier and did away with the company retirement plan. It barely passed because all the lower guys voted for the big one time raise that screwed their longterm future.