This is an opinion and an assumption.  It is not known which will "win" or even that the a fork to increase blocksize would get enough traction to be noticed.


There has been significant debate about this between many of the developers as well as many of the members of the bitcoin community.

There are significant issues on both sides of the debate.  Increasing the blocksize too much can result in driving small mining operations out and can result in significantly less people running full peers.  This could result in a substantial reduction in the security of bitcoin.

Additionally, if a consensus can't be reached among all users the blockchain would split.  Coins received prior to the split could be spent on both blockchains.  Coins received after the split could only be spent on the blockchain where they were received.  In some circumstances, if someone receives "split" coins on one blockchain, they could potentially steal the same coins on the other blockchain without knowing the private key since the required signature would be the same.

As caveden stated, there would be lots of "turbulence".  You might even call it chaos. It is difficult to predict what would result from the chaos.  Perhaps there would end up being two stable coin systems that both have substantial support and coexist.  Perhaps one blockchain would eventually die off as people chose more and more to use the other.  Perhaps the chaos would damage the faith people have in bitcoin enough for both blockchains to die as people migrate to some other currency entirely.