Perhaps, Jason, or perhaps not. But that's one huge gamble to take.
Right now open exists, you and I play in it. But so does the group option, which has the largest single 'faction' in sci-fi gaming history playing it. Mobius has more members than the entire present day Eve Online player base! I don't know how many of us regularly play in open, or how many in PGs, or how many in solo, but if I were DBOBE or FD I'd be extremely reluctant to throw that dice.
It's certainly possible that tons of players would come pouring in and the devs could create a PvP masterpiece with the increased funding. Huzza! [hotas]
It's more likely that far fewer dedicated, long term players would join the game than would leave if you force all the PGs and soloists to play victim for someone else's enjoyment. That's not just my opinion, it's a reasonable extrapolation based on what's already happened in numerous other titles all the way back to Ultima Online.
In games where there are options to play as something other than a player killer most people gravitate toward more constructive roles. Some of those will be white knights, standing up for newbs, some will be grey knights, bounty hunters, player factions and the like, while some will be non combatants.
When the knights can't protect the non combatants, the noncoms will get fed up being slaughtered for someone else's amusement and just stop playing. With no-one to protect, the knights will lose interest and stop playing. With only other player killers in the game, most PKs will leave. You can't mine salt from players of similar skill armed with equivalent weapons!
I don't want to see open banned, but tbh the game could probably survive losing it a lot better than it could losing either of the other modes. Elite has always been a single player game, the option to join some mates and play together in group is what FD push in their advertising campaigns. Open, on the other hand, just seems to be a concession to the popular notion of what a MMO should be. As far as I can see the only real advantage of playing in it is being able to talk tough on the forums...