The two block chains would be nearly impossible to reconcile because Thomas made them two different p2p networks and protocol versions. And ixcoin.2 would be mostly abandoned and ixcoin.1 would be retargeting in 2150.
The old .1 blockchain is useless, wasted resources if you hash on it. You can't stop the new chain to reach block 20055, then the new retargeting gets active. It all depends on the new chain, if exchanges and pools are switching... Mining on the orphan chain won't have any effect on the new one. The people who support the new chain will switch, and this new support will define the value of the new chain...
What defines the value of the chain is the people who mine on it and use it to transact in. Otherwise it is rubbish.