Just speaking hypothetically. If some billionaire decided to buy every bitcoin he could get his hands on and there were only 1 million in that could be traded, do you think bitcoin would survive or would another currency be adopted?
Ok it "only" took a few hundred million USD (at most) of buying to blast the exchange rate from $13.53 on January first to $266 one hundred days later.
So the exchange rate would rise so fast that the billionaire, even Carlos Slim, would run out of money long before the market would give up millions of bitcoins.
But I think your point is, if 90% of bitcoins were held by speculators who could dump them in an instant versus maybe 50% of bitcoins being used as a trading currency, would bitcoin still be able to survive?
I think we are already above 90% of that, except it is not a single billionaire that holds them, it is hundreds of thousands of individuals -- not all of whom would be willing to dump them at the same time. So yes, it is bad for bitcoins to be concentrated in fewer hands than in many hands.
[p.s., Please update the title with something related to your question. "Question for everyone" is a pretty generic title.]
