The switch to PoS is due to the fact that PoW is unsustainable - those miners who have made massive investment in GPUs to-date are experiencing rapid diminishing returns with these DAG sizes - 'they may' swtich to ETC just to get a little more life out of their rigs, but there is no sense in them continuing to load up on hardware for ETH. ETC, if it has a future (which I doubt - it should not), will face the same need.
Those serious folks who wish to use the technology are not going to go with a bunch of opportunistic malcontents, they will follow those that created the tech in the first place. There is very little chance that ETC will overtake ETH in its current state/price/etc, and def not in the future, as the most capable developers will be working on ETH, and it will be there where the real advancements are made.
ETC is a short-term novelty that some have made a decent profit pumping and trading, but its end is nigh.