+1
There are currently about 1.3 quadrillion units of BTC. Each one can be used as a unit of account, bit of currency, speculative investment, etc. Some services already have options to display account balances in mBTC. However, we need more services to implement such features as the default display for laypeople who might have a hard time understanding this concept.
The early miners will not become the Rothschilds. There are too many early miners and they have all sold or spent BTC along the way. BTC wealth distribution is more equal than fiat distribution, and there is still more to be distributed, more than 30% actually.
I'm not sure where you get the info that early miners have sold or spent. The last piece of info I read indicated that 1000 people own about 50% of the as-of-yet mined coins. It's actually currently distributed more unequally than fiat.