I am talking not about giant companies. I am talking about relatively small websites. User auditory of 10 million people is enough to launch bitcoin killer.
Why would they do that? What makes Bitcoin, would be destroyed in the process IMHO. First, probably centralized network, so, controlled. Two, being a company, they would have to play by big gov rules. Three, given one and two, how that creation would be different from dollars and make users jump on it? If you like getting screwed, there is PayPal there for you.
Part of appeal of Bitcoin comes from the fact that this is basically a guerilla network, uncontrolled, no masters, no fear, everyone is equal and has equal opportunity to profit from this system. Nobody can shut you off from your resources, nobody knows how much you have and how you spend it. Proprietary currency would have none of it.
First - not exactly. Centralized only emission. Company will just sell all initial coins. To the end uses (not miners) this is don't play any role. Then - decentralized use on bitcoin principles.
Second - different countries, different rules. Big company always can find country that can support such thing.