I think maybe we need to define crypto-currency. I was speak of system devised by Satoshi a peer to peer distributed currency that requires no trusted 3rd party for validation.
The question is if consumers will make that distinction; if enough consumer dont, then you have competition even if the competing systems arent p2p.
If they do, it still wouldnt preclude any corporation (or government for that matter) from launching one. Just about every second poster on this forum seems to have started an alt chain at some point. They might tinker with it, like giving themselves the option to generate coins with no mining, premine a shitload of coins, make it so that the mining only works on their devices (think gaming console) or who knows what. Frankly, I have no idea what they could come up with, but Im not going to assume there is not going to be fierce competition for bitcoin.
No company like Sony is going to ever use a Sony p2p currency only for use in Sony land. There is no advantage of using a p2p currency in a centralized system.
Why not? After all the hacking incidents, Sony might get the idea that p2p is more secure than centralized. Im sure they could come up with a mining algorithm that can only work with their hardware. I mean, thats just one thought: you can obtain SonyCoins by just running your console or sony laptop. Each playstation game or sony movie you buy gives you some key that allows a higher hashrate or mine on other chains within the SonyCoin system that would have a lower difficulty. Dont ask me how, I got no clue, and if I had, Sony would have to pay me for the idea :p
It is massively inefficient to do so (there is significant overhead in blockchain that can be easily handled by a trusted 3rd party = Sony). Simply put Bitcoin is HORRIBLE inefficient it just happens to be the only way to handle commerce without a central trusted 3rd party. If you have a central trusted 3rd party you don't need Bitcoin or any p2p currency.
SonyCoin could be made orders of magnitude more efficient by limiting the devices that can mine by relying on some builtin TPM module needed to sign hashes or something.