I would not bet on the outcome of such a fork, and I would not be so sure of the outcome either. Having prediction markets for this type of thing is interesting though. I would be happy as long as either side can have the Bitcoin they want regardless of the support that they gain. I do not see any reason why two chains with the same genesis block can not live side by side in peace.
Jeff Garzik does actually support hard forking in order to increase the blocksize, he has also even recently spoken out against Core pointing out some of the same grievances we have. I would recommend that everyone reads this:
http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-December/011973.htmlThere are several reasons that makes a hard fork without super majority (e.g. two parallel chains) dangerous
1. It broke the promise of limited total money supply
After each fork, the amount of total bitcoin in the whole ecosystem almost doubled. This is even worse than FED, they never double the money supply in a single day! So people will find out that no matter whatever reason, this bunch of developers are not any more trustworthy than central bankers, they better return to their fiat money and forget about bitcoin altogether
2. Suddenly increased money supply will destroy the long term perspective of bitcoin
Once forked, you have hyperinflation, the promise of long term deflation is broken, the coin value start to drop long term wise, and there is no hope it will pick up again: Who knows some day these guys will bring another fork and double the amount of money supply again?
3. It broke the promise of trustless network
Now people will understand, by forcing a fork without other's consent, you can change any rule in the current system, including the money supply schedule, network communication protocol, or even who can spend your coin. The fate of your bitcoin barely lies in the hands of a few developers, you have to trust them and worship them not ruin the whole thing
Basically a controversial hard fork destroy the trust in bitcoin and then no one will be interested in it any more
And just because of this, anyone who understand a little bit more about bitcoin will strongly against it. So they will prevent the hyper inflation by instantly sell the weaker fork into alt-coin level value and once that coin's value has crashed, miners will immediately leave it due to the loss of mining worthless coins, it will end pretty quick
Jeff supports a hard fork with super majority, I think 2MB is the easiest to reach, or at least everyone can live with (1MB is currently the super majority)