Do you think it is possible for the Vitalik to dump his ETC to the people who want to keep the ETC?
Done long ago. 115 millions ETC was traded already.
If you can extend that logic, then all the premined ETH have changes hands. No original owners own that.
Of course not. Given the uncertain future, best is to hedge ETH with ETC. Ideally, you should put equal value in both if you are totally unsure about which one will "win" (if any), which means that you should trade about 3/8 of your ETH holdings for ETC. (assuming that the ETC price is about 1/8 of the ETH price). In that case, you already had 1/8 of your value in ETC and 7/8 in ETH, and you're adding 3/8 to it (while losing 3/8 of ETH), so that you obtain 4/8 of your value in ETH and 4/8 of your value in ETC.
That would be the "maximum entropy" hedge, if you are totally ignorant about their future rise or fall in value.
In reality people seem to make another estimation (give it a higher chance that, say, ETH will double, rather than that ETC will double) and hence assign a different ratio to their wallets. This is essentially what their market price ratio indicates. There are probably people not hedging at all, and purely holding ETH (or purely holding ETC), but I guess most will hedge some.