Block height has nothing to do with it
The proof of work threshold for a block (aka the difficulty) was the same when the fork started. The function that adjusts the difficulty (a function of time-between-blocks) is the same across both forks. It would take considerable time for the non-fork chain's difficulty to adjust to where it can make blocks at pace with the fork chain again. And even if it did, the fork would represent less work due to a lower difficulty.
Post-bailout Ethereum is not the same currency as pre-bailout, and given that a non-trivial minority (~5%) of miners are mining pre-bailout Ethereum - and the difficulty of mining quickly adjusts - pre-bailout Ethereum will actually be a viable currency from a technical perspective, in the sense that it can be sent and received.
From a social perspective, it's hard to be sure quite yet; we'll see in the coming days and weeks whether or not people decide that pre-bailout Ethereum has value or not (and equally, post-bailout Ethereum).