I guess the best answer to that question is of course a BIG NO! Granted, China is a big contributor for the rise and adoption of Bitcoin and they are primarily the country involved with Bitcoin mining due to very cheap electricity cost.
Now, the Chinese government has its own agenda and I think in the long run Bitcoin can be running against those agenda so they are now thinking of slowly disengaging and disconnecting their citizens away from the cryptocurrency platform.
I know that whatever China will decide on the impact can be heavy on the market and this is shown with the recent decision banning the ICO projects and the unconfirmed total ban of Bitcoin exchanges though it is still a rumor and nobody would want to confirm.
Can cryptocurrency still go on and have a very optimistic future even without China as part of the equation?
Its a big NO, China always say that they are going to ban bitcoin and the market will go down, don' t you know that its also a strategy for them to sell at the high price and buy on lower prices. And a lot of player and mining companies are all in China, and the people on China are all business minded people so why would they ban a treasure that they will sure get a lot of easy profit without doing too much effort. An almost everyone knows that Almost gadgets products are almost made in China, so they wont slip and ban bicoin.