Re: What prevents one large player from buying up most coins?
This goes back to a game theory, someone did a presentation a couple years ago at one of the conferences. I think it was called brower theorem. What happened is that the buyer gained no benefit. Consider this, you're playing the game of monopoly and the paper slips of money have value because the other players need it. If you have all the money, it's not as valuable because the other players can't use it. At some point, the value of what you hold loses value as a commodity.
Bankster McEvol is not trying to become fabulously wealthy from BTC. If he sees it as a threat, he destroys it, at a nominal cost to himself. Think of it as our immune system attacking our own cells to get rid of a virus.
Quote
A bank could buy all the bitcoins available to destroy it, but then everyone could just use Bitcoin2, etc. A similar situation happened on testnet, some a-hole started supermining all the testnet coins to sell them, so testnet was reset. 
Truth in numbers goes both ways.
So if you just lost a fortune because Bitcoin 1 became worthless, you'll magically get more fiat & invest that in Bitcoin 2 (which will also become worthless)? Truth in numbers goes both ways.By the time we get to Bitcoin 3, even the True Believers would learn to stop throwing away their money.