AKA, The Ramifications of Anonymous Personal Data and Money on Government and Society.
http://www.wired.co.uk/news/archive/2013-03/20/bitcoin-spain-currency-runhttp://www.bbc.co.uk/news/technology-21863593http://www.bbc.co.uk/news/technology-21427505Forget that taxes - or rather, the punishment for not paying something which you never agreed to pay - are a declaration that you are not a sovereign entity, but are the property of your government. The basic question which relates to the thread title is: Why? The answer, of course, is: Because the government can't tax what it doesn't know exists in whose anonymous stash stored who knows where.
People do not want the government to control their trade value. If the government can't control people's currency, it can't take a part of it for themselves, which means it can't fund its efforts to continue to control people's currency, or anything else at all, for that matter. Governments will soon no longer have the ability to exist, because they simply won't be funded - and there's nothing they can do to stop that bit of social evolution.
Does that mean we won't have social services anymore? Not at all. In fact, the services we have will likely be of higher quality, and be much more efficient and tailored to a "country"'s specific cities and smaller regions. Social projects will be funded through
Kickstarter-type operations, with contractors, corporations and individuals listing the projects they think up, and where everybody will have direct say in where
they place their anonymous currencies - not where their government places it for them. This means that services will start to be a lot more like what the people want to see, and funds will transfer relatively directly to projects rather than funneling through inefficient and incompetent bureaucracies.
There will definitely be smaller defense forces all across the globe (albeit with dictatorships, like North Korea, retaining their military might the longest - as they'd be slowest to adopt, and likely block out access to these currencies through force), but probably larger scientific funding across the globe. People will inevitably have more funds at their disposal, as huge amounts of currency are wasted in governmental bureaucratic fashion - not to mention plain old idiocy.
There is also another thing to consider - how will the anonymous currency market shift, in light of these facts-to-be? Current market-cap growth volumes don't allow enough BTC to go around for full global adoption, and with BTC breaking mainstream news, there will be a lot more demand for it. Either output will have to increase, or there will become several established side-by-side currencies, providing enough supply for all to use.