I know it's impractical and can't be done within probably even a day nor a week, but what would happen if someone very rich would like to spend ~1 billion on bitcoins and buy it all?
At first glance looks like it would be the end. Thinking a bit more it suggests that the later bitcoins would be so expensive that even he couldn't afford it, but he would have so much that could make a huge profit out of it.
If there's someone more literate than me in economics, I'd love a detailed and argumented response.
This has bee discussed before.
1) you go bankrupt as did the Hunt brothers - in there attempt to monopolise silver.
http://en.m.wikipedia.org/wiki/Nelson_Bunker_Hunt2) an amazing feature of Bitcoin not often discussed is if you have them all they become worthless.
So in conclusion even if you think you have the means you don't, and if you were successful you have gained nothing.