There is no worry here. Bitcoin is divisible; 100M satoshi is 1 Bitcoin. You can buy a fraction and you are good to go. If it does become a problem, solutions will develop quite easily. You can issue other things and have them backed by Bitcoin at a fixed rate. Very easy.
I agree with the fact that BTC may be bought via smaller portions - however, I do think the case told here is about the overall amount of BTC in the hands of bigger entities against common retailers.