Having two chains does lower total upside, but having the Ethereum foundation and the vast majority of important developers squarely choosing ETH over ETC is restoring faith in Vitalik's brilliant vision which got so many people excited in Ethereum to begin with.
Also interesting is the relationship between the price ratio of ETC/ETH and the hash rate ratio between the two. For now it appears the hash rate is oscillating around and asymptotically approaching 20%, but devcon will probably surge the prices way up.
It is indeed very fascinating to watch, and I agree with your observations. It'll be interesting to see if ETC maintains interest as profit potential goes down for miners.