You are talking as if BTC will be the only form of currency and store of wealth. It won't be. Your example looks at things in the extreme and does not consider more likely events, Ie it acts as a form of digital gold, get traded like commodity, a way of taking money out of conventional markets etc.
BTC is decentralised, so power is not concentrated anywhere. In terms of holders of BTC, well that's up to whoever wants to accumulate now and who has been historically.
